Examining the Efficacy of Co-operative Learning Strategy on Undergraduate Students’ Achievement in Mathematics

Evidence suggests strong support for innovative teaching approaches in mathematics intervention in universities all over the world and a robust backing has been accorded to co-operative learning pedagogy, which provides strong professional development to teachers on ways of  promoting students’ social skills and aiding them to learn in a constructivist way. There is no doubt that co-operative learning is one of the most extensively documented methods to pedagogy in mathematics but little is known about its efficacy in the Nigerian university education setting. This study investigated the effectiveness of co-operative learning strategy on the achievement in mathematics of 220 university students in Nigeria within the blueprint of quasi-experimental research of Solomon four non-equivalent control group design. It also examined the influence of gender on students’ achievement in mathematics. Achievement in mathematics was measured by the differentiation achievement test with KR-20 of 0.86 and data collected for the study were analysed by adopting the independent samples t-test and analysis of variance (ANOVA). The results showed significant main effect of co-operative learning strategy on students’ achievement in mathematics whereas no significant main influence of gender was found on the dependent measure. Also, there was no significant interaction effect of treatment and gender on students’ achievement in mathematics. Based on the positive effect of cooperative learning strategy on university students’ achievement in mathematics in this study, it is paramount to adjust cooperative learning principles to enhance the needs of universities in Nigeria. Integrating technology to enhance enactment of major pedagogical elements of cooperative learning and to differentiate teaching and learning to improve numerous needs of students may provide a leeway to optimize mathematics results for Nigerian students.

and aiding them to learn in a constructivist way. There is no doubt that cooperative learning is one of the most extensively documented pedagogical methods in mathematics, but little is known about its efficacy in the Nigerian university education setting. This study investigates the effectiveness of cooperative learning strategy on the achievement in mathematics of 220 university students in Nigeria, within the blueprint of the quasi-experimental research of the Solomon four non-equivalent control group design. It also examines the influence of gender on students' achievement in mathematics. Gender was included in this study because of the inconsistencies in the research findings regarding its influence on achievement in mathematics and the importance placed on it in mathematics education research. Achievement in mathematics was measured by the differentiation achievement test with KR-20 of 0.86 and the data collected for the study were analysed by adopting the independent samples t-test and a 4×2 analysis of variance (ANOVA). The 4×2 ANOVA was used to contrast the treatment at four levels (cooperative learning with a pre-test and post-test; cooperative learning with a post-test only; a conventional teaching approach with a pre-test and post-test; and a conventional teaching approach with a post-test only) and gender at levels (male and female). The results show a significant main effect of co-operative learning strategy on students' achievement in mathematics, whereas no significant main influence of gender was found on such achievement. In addition, there was no significant interaction effect of treatment or gender on students' achievement in mathematics. Based on the positive social effect of cooperative learning strategy in raising university students' achievement in mathematics in this study, it is paramount to adjust cooperative learning principles to enhance the needs of universities in Nigeria. Integrating technology to enhance

INTRODUCTION
This study assesses the efficacy of cooperative learning in tertiary mathematics, in terms of students' achievement during lessons. At the university level, mathematics educators are always motivated to advance student performance and achievement in the subject area. The concerns over learning difficulties in mathematics and the dearth of metacognitive consciousness of mathematical intelligence and creative problem-solving skills (Tarmizi & Bayata, 2012) appear to continue, and despite variances amongst educators regarding the most effective learning practice, it suggests that there is a slightest consensus concerning the low level of success amongst students in mathematics (Ali, Hukamdad & Khan, 2010). At higher levels, mathematics is regarded as a difficult and uninteresting subject by many students, with weaker students showing not only anxiety about it, but also displaying low mathematics self-efficacy and negative attitudes. Students who are deficient in mathematics proficiency are less successful and perform poorly in university tests and examinations. This low proficiency in mathematics reveals that students are not actively involved in constructing and developing knowledge, as they receive mathematics knowledge passively and are less motivated and less inspired to learn the subject successfully. The passivity in mathematics classes around the world has triggered much apprehension among educators because mathematics knowledge serves as a catalyst for improving a country's social and economic growth and development. The teaching method adopted in mathematics classes can be one of the factors that renders students inactive and less interactive with each other when undertaking mathematics tasks. For the last 35 years there has been a reform of the mathematics education programme as a response to discontent with traditional teaching methods (The Education Alliance, 2006). Particular reports endorsing the reformation of mathematics teaching (National Council of Teaching of Mathematics [NCTM], 1989) have brought about the need for alterations in educational practice.
The NCTM (2011) recommends a move away from conventional mathematics classrooms to reform-oriented ones that focus on effective pedagogical mediations allowing students to be actively engaged in cooperative settings. Employing several models and methods of constructing topics can promote excellent adaptations of the content to better support student's desires in maths (NCTM, 2011). Educators should be more concerned with promoting active learning activities that will ensure students' construction of knowledge in mathematics, and one effective way of achieving this is to acquaint students with cooperative learning (NCTM, 1989;Davidson, 1985). The present adoption of the lecture mode of delivery in universities shows that students are learning mathematics through traditional behaviouristic methods (Tarmizi & Bayata, 2012), which often makes them unreceptive and reliant on their lecturers (Wood, Cobb & Yackel, 1991). Contemporary mathematics teaching centres on a constructivist approach, which helps students to adopt prior knowledge in mathematics to face new challenges, with the hope of obtaining new information for effective and momentous elucidation and in-depth comprehension of the taught material (Amit & Fried, 2002). At the same time, it does not ignore the vital role of traditional instruction in mathematics, and admits that, in a competitive educational milieu, students are more often compensated for individual effort. This study aims to strengthen and expand the previously published literature on cooperative learning, with specific emphasis on mathematics at the university level. It is argued that it is possible to make once-disbelieving educators, who have criticised cooperative learning as a difficult strategy which creates group hate in higher mathematics, understand and consider the value and benefits inherent in cooperative learning for their students (Nardi & Stewart, 2003). Cooperative learning has been found to promote educational attainment, improve social interaction, and improve emotional and psychological vigour (Johnson, Johnson & Smith, 2013).
The educational attainment stimulated by cooperative learning can increase students' academic achievement or reduce educational failure; promote cognitive regulation and intelligent assimilation in the school community; aid learners decide their career and educational goals; increase the chances of virtues they may achieve intellectually; enhance educational pledges; promote tendencies for scholarship; and enhance analogy amid cognitive motivations and school curricula. In addition, the positive social interactions nurtured by cooperative learning practices can promote shared pressure to study and accomplish tasks; regulate to fresh interactions and turn out to be informally integrated into school culture; help promote group goals; diminish improbability about goals; promote obligations to colleagues; and enhance similarity amid going to school and rapport goals. Moreover, the improved emotional vigour endorsed through cooperative learning practices can improve students' educational self-worth and confidence; emotional regulation; elucidate individual goals; improve the capability to manage insecurity; encourage productive interactions with different school colleagues; establish alliances in order to attain goals; and provide the capability to adjust one's goals to present conditions. Although cooperative learning has been extensively adopted in schools worldwide, with a rich, impressive and solid research base (Johnson, Johnson & Smith, 2013;Celikten, Ipekcioglu, Ertepinar, & Geban, 2012;Johnson, Johnson, & Holubec, 1994), there is a dearth of research on how working in cooperative learning environments influences Nigerian university students' academic achievement in mathematics (Awofala, Fatade & Ola-Oluwa, 2012). This study therefore examines the efficacy of cooperative learning in university-level mathematics, which is perhaps somewhat lacking in research output in Nigeria, by investigating enhanced student achievement after the implementation of the cooperative learning interface.
Cooperative learning is based on the theoretical frameworks of social interdependence, cognitive development, and behavioural learning. Evidence suggests that it takes a greater effort to accomplish, but leads to more positive relationships and greater emotional health than competitive or individualistic learning efforts (Johnson, Johnson, & Holubec, 1994). Social interdependence theory perceives cooperation as a result of positive links between individuals in achieving a common goal. Kurt Koffka anticipated in the early 1900s that although groups are vibrant wholes, interdependence amongst members varies.
Such interdependence developed from shared goals provides the indispensable kernel of a group (Lewin, 1948), thus creating the vibrant whole. The power of a group is such that the modification of any member or subgroup directly alters other members and subgroups.
Whenever two people work together, the likelihood of cooperation occurs. For this to develop in students, the following conditions must be satisfied. Based on social interdependence theory, these conditions are group processing, individual accountability, social skills, promotive interaction, and positive interdependence (Johnson & Johnson, 1989, 2005. Within cognitive development theory, cooperation must go before cognitive growth. Such growth evolves from the configuration of various viewpoints as individuals work to reach common goals. Both Piaget and Vygotsky believed that cooperative learning with academically stronger peers and instructors produced cognitive development and intellectual growth (Johnson, Johnson & Smith, 1998). The supposition of behavioural learning theory is that students will work hard and show perseverance on tasks that provide a reward contingent but that they will be reluctant to do so on tasks that provide no reward or punishment. Cooperative learning is one pedagogical strategy that gives rewards to individuals for participating in the group effort. It is a mode of learning in which students of different ability levels work together in small groups to develop both academic and social relationships, cross-examine issues, share ideas, elucidate differences, and construct new understanding to accomplish a common group goal. Such learning not only encourages students to be active contributors in the construction of their own knowledge (Webb, Troper, & Fall, 1995), but also allows them to network and converse with peers in agreement. Therefore, cooperative learning could be seen to be promoting values such as trustworthiness, teamwork, shared esteem, accountability, patience, and eagerness to sacrifice an agreement.
Despite the thousands of studies conducted on cooperative learning world-wide in the last century, the new millennium has witnessed increased research on cooperative learning in mathematics at the primary and secondary school levels (Celikten, Ipekcioglu, Ertepinar, & Geban, 2012). This avalanche of research on the use of cooperative learning strategies agrees that students at primary and secondary grade levels experience growth in their achievement in subject areas, increased understanding of given topics, and a rise in motivation, and that cooperative learning leads to productive and valuable results for student learning (Celikten et al., 2012;Kilpatrick, 1992;Ebrahim, 2012;Galton, Hargreaves, & Pell, 2009;Law, 2011;Souvignier, & Kronenberger, 2007;Tarim, 2009;Pierce, Cassady, Adams, Speirs Neumeister, Dixon, & Cross, 2011).
The literature includes many studies conducted to examine the effectiveness of competitive, individualistic, and cooperative methodologies in improving productivity and achievement (Johnson & Johnson, 1990;Johnson, Johnson & Smith, 2013). In a meta-analysis of achievement in cooperative learning, the results showed that average student learning through cooperative methods performed at around two-thirds a standard deviation above the average student learning within a competitive effect size of 0.67) or individualistic (effect size of 0.64) structured lesson (Johnson, Johnson & Smith, 1991). These results showed the efficacy of cooperative learning in increasing the achievement levels of students compared to competitive or individualistic learning strategies. According to Curtis (2001), cooperative learning deals with tasks that are dividable into more or less autonomous subtasks, where cooperating teams work together to process discrete subtasks in an independent, self-governing way, which is different to collaborative learning, in which a joint solution to a problem is constructed concurrently, mutually and in connection with all members of the group.
Since learning mathematics at higher levels is often seen as a lonely, individualistic or competitive activity, with students exhibiting anxiety and showing avoidance behaviours, cooperative learning can overcome these problems and facilitate students' growth and attainment in the subject (D'Souza & Wood, 2003). Mathematics provide the opportunity for innovative thinking, and exploring open-ended questions and intriguing problems, and cooperative learning can help to solve these problematic and challenging tasks that are outside the reach of individual capacities at the growing stage.
Cooperative learning can be a convenient and helpful strategy to help students develop academically and socially. Its academic benefits include higher achievements in reading comprehension (Mathes, Fuchs, & Fuchs, 1997) and mathematics (Awofala, Fatade & Ola-Oluwa, 2012) and enriched conceptual understanding and achievement in science (Lonning, 1993). The social benefits may include perseverance in tasks and the facilitation of interactions with group members (Burron, James, & Ambrosio, 1993;Gillies & Ashman, 1998;McManus & Gettinger, 1996), greater self-confidence, more friends, more participation in classroom activities, and better attitudes toward learning in general (Lazarowitz, Baird, & Bolden, 1996;Lazarowitz, Hertz-Lazarowitz, & Baird, 1994). Such learning can sometimes be less successful because of the reduced comprehension of the vital components that mediate its efficacy. For example, weaker members of the team can sometimes leave team exercises for others to complete, whereas strong team members might neglect exercises by putting in less effort to avoid doing all the work. However, the co-operative learning that is commonly undertaken in schools comprises amorphous group work, with little individual responsibility and no common group goals (Stein, Grover, & Henningsen, 1996;Hiebert & Wearne, 1993). The failure of cooperative learning can be explained in terms of student characteristics. For instance, students who were accustomed to learning passively from teachers, taking notes, and preparing for tests and examinations individually would find it extremely difficult to engage in active investigation of a topic, acquire information by themselves or from their peers, or to learn in teams. In this case, students would experience difficulty in researching topics because in a competitive environment they did not have to conduct research, but rather record the material that teachers presented in the class. Therefore, this passive learning culture completely negates the cooperative learning principle of students being active and independent in their learning.
It is a fact that the amount of time spent on explaining concepts can be directly and positively related to the amount of time spent on learning, so the stronger members of a cooperative team can learn much by giving detailed elucidations of the taught material to the weaker students who are struggling to understand it (Kerr & Bruun, 1983). Mathematics educators play a significant role in the effective implementation of cooperative learning in the classroom, as they act both as content analysts and classroom administrators (Johnson & Johnson, 1990), who are able to identify the specific behavioural objectives of the lesson, make pedagogical decisions, and explain tasks showing the assignment goals (Smith, 1996) for the realisation of the learning outcome. The three null hypotheses formulated and tested in this study at the =.05 level of significance are: a. There is no significant main effect of treatment (cooperative learning strategy and conventional teaching approach) on university students' achievement in mathematics; b. There is no significant main influence of gender on university students' achievement in mathematics; and c. There is no significant interaction effect of treatment or gender on university students' achievement in mathematics. Note that an interaction effect is the concurrent effect of two or more independent variables (in this case instructional strategy at two levels and gender at two levels) on at least one dependent variable (in this case achievement in mathematics), in which their joint effect is significantly greater (or significantly less) than the sum of their parts.

MATERIALS AND METHODS
This study adopted a quantitative research approach within the scheme of quasiexperimental design. The non-equivalent Solomon four control group design was implemented to test the null hypothesis. The design was carefully chosen because it was not possible to randomise students to groups comparatively because the unit of sampling, a class, had already been formed. Therefore, it was unprincipled to reorganise one randomly. In addition, undergraduate classes exist as intact groups with definite times for lectures, which may pose difficulties in reconstituting them for research purposes (Gall, Borg & Gall, 1996). The research design is shown in Figure 1. In the follow-up, O1 and O3 were pre-test. The pre-test is the preliminary MAT given to participants before the commencement of treatment. O2, O4, O5, O6 were the post-test. The post-test is a rearranged MAT given to the participants after the completion of the treatment or instructional programme. X was the treatment by which students were taught using the cooperative learning strategy. The dotted line refers to the participation of whole groups, and the design involved an arbitrary allotment of intact classes to four different groups. Group E1 was the experimental group, which was given the pre-test, treatment X and the post-test. Group C1 was the control group, which was given the pre-test, followed by the control condition and then the post-test. Group E2 was given treatment X and the post-test, but not the pre-test, while group C2 was given the post-test only as it was the control group. Groups C1 and C2 were given the control condition of the lecture method, while Groups E1 and E2 were treated with the experimental condition of cooperative learning. This design prohibited all major threats to internal validity, apart from those associated with interactions of selection and maturation, selection and instrumentation, and history. No major event was detected in any of the sampled universities that would have justified interaction between selection and history. To control for interaction between selection and maturation, the universities were assigned arbitrarily to the control and treatment groups. To control for interaction between selection and instrumentation, the conditions under which the instrument was administered were kept as similar as possible in all the universities (Awofala, 2016a;Shihusa & Keraro, 2009).
The target population for the study consisted of all BSc Education degree students taking mathematics in four public universities in the states of Lagos and Ogun in southwest Nigeria. This geo-political zone was chosen because it has the highest number of universities (public and private) and is regarded as the cradle of higher education in Nigeria. An intact class of first year mathematics education students (freshmen) was purposively selected from each university. Purposive sampling was used based on the following criteria: each intact class must comprise students studying BSc. Ed mathematics and must be a first year class, in which calculus is taught. Each intact class of the first-year mathematics education students from each university was randomly assigned by the simple random sampling technique to experimental groups I and II and control groups I and II. Overall, the sample consisted of 220 students (112 females and 108 males), whose mean age was 20 (SD=2 years 2 months). The selection of these students was considered appropriate, since older students in the university seem to benefit more from cooperative learning than younger students at secondary school. The reason for this is attributed to the fact that older students possess more developed schemata for processing information in a real-world context (Awofala, 2010) and taking on active roles in co-operative learning to gain social skills is never a problem for them. Table 1 shows the distribution of the students in the four groups. One instrument, the Differentiation Achievement Test (DAT) was used for the data collection. The DAT, which was used to assess the achievement of students in differentiation, was developed by the researchers. The DAT used as the pretest and post-test consisted of 30 multiple choice items with options A to D and covered topics related to differentiation of algebraic functions, differentiation of trigonometric functions, differentiation of composite functions, chain rule, quotient rule, and derivatives of implicit and parametric functions, as contained in the first year handbook of undergraduate mathematics. The initial 40 items of the DAT were subjected to face and content validation by two mathematics lecturers at the University of Lagos, Akoka, Lagos, Nigeria. The validation involved checking the DAT items against the topic of the lesson plan, language editing, and suitability of the test for the target participants. Five items were removed based on the experts' recommendations and the face-validated DAT was verified for difficulty index and discrimination power. Items with a difficulty power of 0.4-0.6, discrimination power of 0.2 and above, and distracter index of negative decimal were retained (Akinsola & Awofala, 2009). In line with this, five items were omitted, leaving the final 30 items for the DAT, which was trial-tested with 80 first year undergraduate mathematics students in a university not taking part in the study. The reliability coefficient of the DAT was found to be 0.86 using Kuder-Richardson 20 formulae. Each item on the DAT was scored with up to 1½ marks, meaning a total score of 45 marks was attainable. The DAT covered the last three levels of the Bloom taxonomy of cognitive domains, known as the higher-order cognitive domain (analysis-A, synthesis-S, and evaluation-E), as shown in the specification table (  Total 10 10 10 30 The study was conducted over seven weeks and involved four classes with a mathematics lecturer in each one. Therefore, a total of four mathematics lecturers were recruited for the study. During the first week, students responded to one instrument, i.e. the Differentiation Achievement Test as the pre-test, while treatment commenced in the second week and lasted for five weeks. The seventh week was used for the administration of the post-test DAT. In the experimental groups, students were assigned to mixed-ability teams of four or five members. Each chose a team name and was given the responsibility of ensuring that every team member learnt the content presented in their mathematics lessons. In each lesson, after initially explaining a target concept, on a whiteboard teachers posed a series of problems for students to solve in a "team huddle." They then called on a student at random from each team to represent the team with their answer and explanation. Because the students did not know which team mate would represent them, they had to ensure that all the members understood each problem and solution. The lecturers provided guidance and support during the team work activities, observed the team interaction and provided hints or clarifications and encouragement, bringing members into the discussion, acting in a pleasant and productive manner, and interceding when necessary in an encouraging way in order to ensure successful accomplishment of the task by the team. As the teams completed the problems, the results were exchanged among them for marking and to provide appropriate feedback to their peers. By this strategy, students not only deepened their understanding of the theory with the help of their classmates, but they also learned to talk together, to iron out issues, to evaluate and correct their mistakes, and to gain social skills. Finally, all the students were individually assessed, and teams were evaluated based on the average performance of all the team members. The control classes had their teaching and learning experience delivered under normal traditional arrangements throughout the five weeks. All the students who were exposed to co-operative learning and took the pre-test and post-test were classified as Experimental group I (E1) or Cooperative Learning I (n =55); those who were taught with a conventional teaching approach and took the pre-test and post-test as Control group I (C1) or Conventional Teaching I (n =60); and those who were exposed to co-operative learning and only took the post-test were classified as Experimental group II (E2) or Cooperative Learning II (n =50). The students in Control group II (C2) or Conventional Teaching II (n =55) received a conventional teaching approach and only took the post-test.
The collected data were analysed using the descriptive statistics of mean and standard deviation, which served as precursors to adopting the inferential statistics of 4×2 Analysis of Variance (ANOVA), and the independent samples t-test. The two-way analysis of variance examined the influence of two different categorical independent variables (treatment and gender) on one continuous dependent variable (achievement in mathematics). It aimed to assess the main effect of each independent variable and also if there was any interaction between them (Gelman, 2005). ANOVA was employed to determine if the four groups differed significantly with regard to the experimental variable. An independent samples t-test was used to assess the differences in the pre-treatment (post-treatment) mean scores of the dependent measure between the experimental and control groups (with male and female participants) because of its superior quality in detecting differences between two groups (Awofala, 2016a).

RESULTS
In this part of the study, the results are presented based on the null hypotheses formulated. First, the assumption was that the two groups studied were homogenous. Consequently, the author sought this homogeneity in terms of their responses to the pre-treatment achievement test before the application of the treatment procedure (Awofala, 2016a;Wiersma & Jurs, 2005). A pre-treatment achievement test was administered to the two groups, experimental group I (E1) and control group I (C1). Table 3 shows that the mean for group E1 was 21.53 (SD=4.59), while that of group C1 was 21.50 (SD=4.40), meaning that of the former was slightly higher. Likewise, the standard deviation of group E1 was slightly higher than that of group C1. This means that the scores of group E1 spread away from the mean, while those of group C1 were closer to the mean. Therefore, the level of achievement between groups E1 and C1 was not significantly different [t (113) = 0.33, p>.05], hence they showed similar features and were therefore found to be relevant for the study. The results in Table 4 show that the mean score for male students was 21.48 (SD=4.44), while that of their female counterparts was 21.52 (SD=4.34). The tvalue was 0.06, which showed that a statistically non-significant difference existed in mathematics achievement between male and female students. This nonsignificant difference in mean scores for both the pre-treatment groups and for gender necessitated the use of ANOVA to analyse the difference between the four groups in the post-treatment DAT scores. .59) and C2 (mean=23.22, SD=5.12), but the students in groups E1 and E2 recorded higher mean scores than those in groups C1 and C2. This shows that the students in the experimental groups I and II taught mathematics with the cooperative learning strategy performed better than those in control groups I and II, who were taught with the conventional teaching method. Hence, the co-operative learning strategy was more effective than the conventional teaching method. Further analysis of the post-treatment achievement scores of the students in experimental groups I and II and control groups I and II using the analysis of covariance shown in Table 6 indicates that the difference in means between the four groups was statistically significant (F(3, 219)=62.95, p=0.000, η 2 p=0.471). The partial eta squares(η 2 p), which is the proportion of the effect + error variance that is attributable to the effect (Awofala, Fatade & Udeani, 2015) was only 0.498, which means that the factor treatment by itself accounted for only 47.1% of the overall (effect + error) variability in the university students' mathematics scores. This result suggests a large effect of treatment (Cohen, 1988). A significant result at a level of p<0.05 means that there is a less than 5% chance that the result is simply due to randomness. The flip side of this was that there was a 95% chance that the difference in post-treatment achievement scores between the four groups was a real difference and not just due to chance. As observed in Table 6, the twotailed p value was 0.000, which means that random sampling from identical populations would lead to a difference smaller than was observed in 100% of the experiments, and greater than was observed in 0% of the experiments. Therefore, null hypothesis 1 was rejected and it was concluded that there was a significant effect of treatment on university students' achievement in mathematics. After establishing that there was a significant difference between students in the four groups, it was appropriate to further confirm the direction of the difference. This was accomplished by post hoc tests of multiple comparisons using Tukey's honestly significanct difference (HSD) test (Montgomery, 2013). This test was deemed suitable for the study because a large number of groups were being compared and the test helps in reducing the likelihood of a Type I error occurring by identifying differences between groups. The results indicate that the differences in the mean scores of groups E1 and C1, groups E1 and C2, groups E2 and C1 and groups E2 and C2 were statistically significant (p.05), but that there was no statistically significant difference between groups E1 and E2 and groups C1 and C2.  Null Hypothesis Two: There is no significant main effect of gender on university students' achievement in mathematics. Table 5 shows that male students had a mean score of 28.38 (SD=6.37) in the post-test while the female students had a mean score of 27.90 (SD=6.53). This indicates that the male students performed slightly better. Therefore, there could still be slight gender difference in maths achievement in favour of male students. Further analysis of the post-treatment achievement scores of the male and female students using the Analysis of Variance shown in Table 7 indicates that the difference in means between the two groups was statistically not significant (F(1, 219)=0.31, p=0.58, η 2 p=0.001). Therefore, it was concluded that there was no significant effect of gender on students' achievement in mathematics.

Null Hypothesis Three:
There is no significant interaction effect of treatment or gender on university students' achievement in mathematics. The results shown in Table 5 reveal that male students taught mathematics with the co-operative learning strategy in experimental group I had a mean score of 32.32 (SD=4.19) in the post-test, while their female counterparts recorded a posttest mean score of 33.33 (SD=3.39). In experimental group II, taught with the cooperative learning strategy, male students had a mean score of 32.92 (SD=3.59) in the post-test, while their female counterparts recorded a post-test mean score of 32.31 (SD=4.30). In addition, male students in control group I taught mathematics with the conventional teaching method had a mean score of 25.00 (SD=6.45) in the post-test, while their female counterparts recorded a post-test mean score of 24.24 (SD=4.57). In control group II, taught with the conventional teaching method, male students had a mean score of 23.80 (SD=4.62) in the post-test, while their female counterparts recorded a post-test mean score of 22.73 (SD=5.53). In light of these results, male and female students in both experimental groups I and II taught mathematics using the co-operative learning strategy gained comparably and maximally from the instruction than those taught in control groups I and II using the conventional teaching method. Further analysis of the post-treatment achievement scores of the students based on treatment and gender, using the analysis of variance shown in Table 6, indicates that the interaction effect of treatment and gender was statistically not significant (F(3, 219)=0.53, p=0.66, η 2 p=0.007). Therefore, it was established that there was no significant interaction effect of treatment or gender on university students' achievement in mathematics.

DISCUSSION
The findings of this study have shown that the co-operative learning strategy enhanced learners' achievement in mathematics more than the conventional teaching method; Slavin and Lake (2008) previously claimed that there was a significant difference between the two approaches. The results show the more facilitative potential of the co-operative learning strategy in promoting achievement in mathematics over the conventional teaching method, thereby supporting the advocates of the former (Awofala, Fatade, & Olaoluwa, 2012;Awofala, Arigbabu & Awofala, 2013). The significant effect of the treatment is consistent with the findings of several studies on student-centred strategies, with co-operative learning being one of these (Lawal & Awofala, 2019;Awofala, 2017a;Awofala, 2014;Awofala, 2011a;Awofala, 2011b;Awofala, Balogun & Olagunju, 2011;Akinsola & Awofala, 2008;Awofala, Fatade & Ola-Oluwa, 2013;Awofala & Nneji, 2011;Ojaleye & Awofala, 2018). However, the significant evidence in favour of co-operative learning strategy is also inconsistent with some findings (e.g., Tracey, Madden, & Slavin, 2010). The presence of a cooperative learning effect on achievement in mathematics in this study was probably a result of many factors.
Co-operative learning is particularly well-matched to mathematics, as it helps students to understand their own misconceptions in the process of engaging in the construction of meaning. Students in a group may all be learning material for the first time, and may be even more aware than their teacher of what other students  (Webb, 2008). In essence, co-operative learning functions as a means of cognitive elaboration, helping students to both learn and understand (Webb, 2008;O'Donnell, 1996;Newbern, Dansereau, Patterson, & Wallace, 1994). One other main reason why co-operative learning strategy is expected to enhance mathematics development is its ability to structure experiences that promote metacognition, defined as knowledge of one's own cognition. Therefore, co-operative learning allows the process of understanding why you know something and how you know it. This might have been the case of the students treated with the co-operative learning strategy in this study.
The non-significant difference confirmed in achievement in mathematics between male and female students in this study reveals that gender has no effect on students' achievement. This supports earlier findings (Awofala, 2017b;Fatade, Nneji, Awofala & Awofala, 2012;Awofala & Anyikwa, 2014), which have revealed no significant effect of gender on students' achievement in mathematics. However, the finding of this study on gender difference also contradict earlier studies (Awofala, 2011c;Awofala, 2008), which established a significant effect of gender on students' achievement in mathematics. The non-significant effect found in this study could be a result of the interaction pattern that prevailed in the classrooms, which did not favour one gender above the other (Awofala, 2016a). Eccles and Midgley (1989) maintain that students are highly motivated to learn when classroom situations are well adapted to their needs, interests, and skill levels. This might have been the portion of both male and female students in this study, because equal opportunities were given to them to learn mathematics. The results of this study indicate the non-existence of disparity in the experiences of males and females within and outside the classroom, and that gender differences in achievement in mathematics might be declining.
The non-significant interaction effect of treatment and gender documented in this study is in line with previous studies (Ojaleye & Awofala, 2018;Ogunleye, Awofala & Adekoya, 2014), which have shown that gender does not seem to interact with instruction to produce results. This means that the treatment conditions did not discriminate across gender in this study. Esiobu (2011) found that there was a significant difference in the academic achievement of boys and girls who were taught biology through the co-operative learning strategy, while Adeyemi (2008) recorded no significant difference in the achievement of boys and girls of comparable abilities when they were taught social studies through cooperative learning strategy. Similarly, Mahira and Azamat (2013) reported no significant gender difference in the mathematics achievement of students who were taught through the co-operative learning strategy. The results of this study imply that co-operative learning could be used to promote learning and narrow the gender gap in the learning of mathematics. Therefore, co-operative learning strategy could be used as a base for personalising instruction for both male and female students to enhance mathematics teaching effectiveness and creativity among mathematics students in Nigeria .

CONCLUSION
This study has investigated the effectiveness of applying co-operative learning strategy in a university-level mathematics course in terms of student achievement.
Considering the co-operative interaction and team solutions, it is clear that cooperative learning helped to deepen students' understanding of the material, which in turn promoted higher achievement levels for the classes that undertook co-operative learning on the specific topic of differentiation. During the intervention, it was further observed that students were critical and seamlessly developed their logical thinking skills whilst working in a team. Less able students, who once would have become frustrated with individual work, exhibited low levels of strain and showed less stress and anxiety when solving mathematical problems in co-operation with fellow team members. Using this learning strategy at the university level in a subject that students always find difficult, and in a topic that students have always found challenging, has led to results that are significant and support the previous work on this ever-popular learning approach. Although the results of this study are positive and support the benefits of co-operative learning, one possible limitation is the relatively short period of co-operative learning. Therefore, one possible improvement would be to consider extending the duration and period of co-operative interaction. Based on the positive social effect of cooperative learning strategy on university students' achievement in mathematics in this study, it is paramount to adjust cooperative learning principles to enhance the needs of universities in Nigeria. Integrating technology to enhance the enactment of major pedagogical elements and to differentiate teaching and learning to improve the diverse needs of students may provide the opportunity to optimise mathematics results and attitudes (Awofala, 2016b) amongst Nigerian students.


Investigating the use of case-oriented station technique in teaching socioscientific issues: A mixed method study

This research aims to investigate the effect of teaching the socio-scientific issues, "Global Warming, Sustainable development and Bio-technology" in 8th class, with the case-oriented station technique on the academic achievement of the students and their motivation toward science learning. The study was carried out with 71 students in 8th class in 2 secondary schools of a district with approximately 20.000 population in the Eastern Anatolia Region. The mixed-method, consisting of the data collected as qualitatively and quantitatively, was employed. In the quantitative part of the study, the Socio-scientific issues Achievement Test and the Science Learning Motivation Scale developed by Dede and Yaman (2008) to measure students' motivation to learn were used. Unstructured interview, which is one of the qualitative research methods, was preferred in order to support the study with student opinions and comments. The Socio-scientific Issues Achievement Test and the Science Learning Motivation Scale were applied to the experimental and control groups as pre-test at the beginning and as post-test at the end of the study. Results indicated that teaching the socio-scientific issues with case-oriented station technique positively affected the students' academic achievements and their motivation toward science learning. Besides, the interviews showed that the students found it useful, fun, remarkable and permanent to learn socio-scientific issues using the case-oriented station technique.

Introduction
Today, with the rapid development of science and technology, the need for manpower to keep up with this development is increasing day by day. For individuals to have the equipment required by the age, a science education arising curiosity in individuals, enabling them to conduct research, study and make an experiment and allowing to know the natural environment has gained significance (Yüksel, 2017). Science education to be provided to students should meet the need to increase the scientific literacy of our community and future citizens (Çepni, 2014). In this context, the science curricula are prepared being updated according to needs, developments and innovations in our country. In 2013, the added objectives to the Science teaching curricula related to the subject studied are as follows (MoNE, 2013):  To realize the reciprocal interaction between individual, environment and society, and raise awareness of sustainable development of society, economy and natural resources.
 To take responsibility for daily life problems and to use knowledge, scientific process skills and other life skills related to science to solve these problems.
 To develop scientific thinking habits by using Socio-Scientific issues (SSIs). The added objectives to the Science teaching curricula related to the subject studied in 2017 are as follows (MoNE, 2017):  This course aims to give basic information about astronomy, biology, physics, chemistry, earth and environmental sciences and science and engineering applications.
 To develop reasoning, scientific thinking habits and decision-making skills by using socio-scientific issues.
 To ensure the adoption of universal moral values, national and cultural values and scientific ethical principles.
Among the objectives added to the science curriculum in 2013, SSIs were directly included in the program for the first time, and in addition to the scientific process skills of the individual, developing responsibility towards social problems and solving these problems were added as the functions. In the updated program in 2017, it is seen that it was aimed to relate the subjects to daily life, adopt universal and national values, develop discussion and decision-making skills.
The SSIs, which are mentioned in the curriculum and the theme of study, is scientific and social issues based on science, including controversial social dilemmas (Ratcliffe & Grace, 2003;Sadler & Zeidler, 2005;Topçu, Sadler, & Yılmaz-Tütün, 2010). Besides, socio-scientific issues are moral and ethical issues that are controversial by nature but have no single consequences (Sadler & Zeidler, 2005). Individuals must reach an effective decision on a socio-scientific issue, evaluate the possible ethical, moral and legal consequences of the issue together, and consider the critical thinking skills to develop socio-scientific issues in the program (Çakırlar Altuntaş, Yılmaz & Duran, 2017). In consideration of this information, it can be emphasized that addressing socio-scientific issues in science classes is an important tool both for the student's personal development and for the development of society (Balkan Kıyıcı, 2008). In particular, decisions on controversial socio-scientific issues in the field of science have created a necessity to form a scientific literate society that can make informed decisions using science's ways of thinking and critically evaluate arguments on the future of societies, and perhaps the survival of our world, allegations put forth in scientific discussions, justifications, reasoning and arguments (Şahin & Hacıoğlu, 2010).
In this context, the case-study method and station technique, which is considered as appropriate to the teaching of SSIs, were applied together in the research. The case study method is the method that has the features that contribute to teaching the socio-scientific issues such as to relate topics to daily life, problem-solving, decision-making, discussion and development of high-level thinking skills. This method necessitates the active participation of individuals both mentally and emotionally. The discussion of moral and social dilemmas in the classroom, where various arguments are contested, different rights and perspectives can be defined, is an excellent opportunity for students to gain perspectives, but also to question their understanding of morality (Aydın, 2007). The station technique, which will be applied with the case study method, is a student-centred technique that teaches how to advance what the previous group has done through the whole class contributing to each stage (at each station) (Gözütok 2006, p.256). In this technique, it is also aimed to uncover the qualifications such as reinforcing topics with activities in different intelligence areas, creativity and cooperation. It can be claimed that the more a content and teaching approach supports the development of skills, the better and more useful it is (Evren Yapıcıoğlu, 2016).
The methods and techniques selected correctly in accordance with the subjects and achievements are necessary and important in terms of revealing the potentials of students at a high level and increasing their academic achievement. In this scope, as the topic forms of the SSIs are taken into consideration, the case-oriented station technique, considered to be suitable for teaching the topics, is believed to be significant in terms of motivating students to the lesson or issue with various activities in addition to increasing their academic achievements, so to increase motivation towards science lesson and to help students develop higher-level thinking skills. Besides, the present study differs from other studies on the SSIs in that it is a study, in which two different methods and techniques are used in teaching SSI and will contribute to the literature.
This research aims to investigate the effect of teaching the socio-scientific issues, "Global Warming (GW), Sustainable Development (SD) and Biotechnology (BT)" in 8th class with the case-oriented station technique on the academic achievement of the students and their motivations related to learning science lesson. In this research, the following 3 research questions were asked in line with the aims of the study: 1. Does teaching the 8th-grade socio-scientific issues (GW-SD-BT) using case-oriented station technique contribute to the students' academic achievements?
2. Does teaching the 8th-grade socio-scientific issues (GW-SD-BT) using case-oriented station technique contribute to the students' motivations?
3. What are the students' opinions after the application of teaching the socio-scientific issues, (GW-SD-BT) in 8th class with the case-oriented station technique?

Research Design
The mixed-method, consisting of the data collected as qualitatively and quantitatively, was employed in the study. In terms of using the mixed-method approach, each event and fact has a qualitative and quantitative dimension that should be investigated. By investigating these dimensions together, it is seen whether the collected data support each other or not. There is not only a single approach to using mixed methods. While quantitative methods come to the forefront in research designs, sometimes qualitative methods can be dominant. In some cases, both methods can be used equally (Yıldırım & Şimşek, 2013). In the present study, the quantitative data were collected, then supported with the qualitative data. In this context, the descriptive pattern was selected from mixedmethod research designs. In descriptive research, data are first collected by quantitative methods, and then qualitative data are gathered considering the analysis of these data (Creswell & Plano-Clark, 2015). The contribution of the data collected by this method to the research is equal (Yıldırım & Şimşek, 2013). The quasi-experimental model, one of the quantitative research methods, was applied. The fact that a study is quasi-experimental shows that the research can reveal the cause and effect relationship and that this result can be generalized with similar results (Can, 2013).
For the research, ethical compliance was obtained from the Human Research Ethics Committee of Erzincan Binali Yıldırım University on 01.02.2018 and with protocol number 01/18. Taking into consideration the ethical committee decision, necessary research permit was obtained from the provincial directorate of national education, where the schools where the research was conducted, through correspondence between institutions.

Study Group
The research was carried out with 71 students in 8th class in 2 secondary schools of a district with approximately 20.000 population in the Eastern Anatolia Region. The sampling method, in which equal probability of selection is given to each sampling unit, is called the simple random sampling method (Büyüköztürk, 2013). The study group was selected with the simple random sampling method consisting of 2 secondary schools out of 3 located in the district, and 2 classrooms out of 4 in these schools. The experimental group consisted of totally 35 students including 16 girls and 19 boys while the control group consisted of 36 students including 17 girls and 19 boys.

Data Collection Tools
The Socio-scientific Issues Achievement Test (SIAT) developed to measure the effectiveness of training and the Science Learning Motivation Scale (SLMS) to measure students' motivations related to learning (Dede & Yaman, 2008) were administered to the control end experimental groups as pre-test and post-test and analyzed.

SIAT Test:
According to the determined gains in science education, a qualified and well-prepared measurement scale is needed to determine student achievements. Although there are several measurement tools applied to find out students' learning, multiple-choice tests are of particular importance in terms of time, preparation, objectivity, usability and ease of application in classroom environment (Ayvacı & Durmuş, 2016). In this scope, the multiple-choice questions including the " Global Warming, Sustainable Development, Biotechnology" in the unit of "Living Organisms and Energy Relations" of 8th class within the context of SSIs were developed as SIAT. Validity is one of the most significant features that should be in a measurement tool. The validity, in the most general and classic definition, what the measuring tool wants to measure is the degree to which it can measure without mixing other variables. The method to determine the validity of a test consists of analyzing the scope of the test, comparing the scores obtained from the test with the appropriate criteria, investigating the structure to be measured in the test (Atılgan, Kan & Doğan, 2009). To provide the content validity of the achievement test in the research, the table of specifications was prepared and expert opinions were received.
To prepare the SIAT question pool, various resources related to the unit were reviewed. Questions with different difficulty levels from the trial exams by the MoNE, from the science course books approved by the MoNE, from the tests of different publishers were selected considering the number of gains in the unit and hours of the course. 43 questions selected were presented to the opinions of 2 academicians and 2 science teachers. Considering the opinions and evaluations of the experts, some questions were omitted and a pilot achievement test consisting of 38 questions was prepared. The pilot achievement test was applied to 85 9th grade students in two different high schools located in the mentioned district in which the research was carried out. As a result of the pilot application, each item in the test was analysed in terms of providing construct validity. The construct validity is related to the concept that the scores obtained from the test assume that the test is measured, that is, to what extent the structure measures (Büyüköztürk, 2013). Item discrimination index (-1.00 to +1.00) varies, but the items with low discrimination rates below .20 should be removed from the test because the discrimination rates are low (Güler, 2011). For this reason, 11 units with a distinctive index below .20 in the test (5,11,16,20,23,28,30,31,35,37,38) were excluded from the test. 2 items (10, 18) with item discrimination index between .20 -.30 were used in the test by correcting the distractors as a result of the evaluations of a science education expert and a researcher. In an ideal achievement test, the average difficulty index of the questions should be around .50 (Güler, 2011). The average difficulty of the test is .50 and 8 easy items (1,2,3,6,8,14,15,22) were also excluded from the test. During the item analysis process, after determining the difficulty and discrimination values of some items, some questions were removed from the test and a final achievement test consisting of 19 items was created.
In the present study, the single-application method , also called internal consistency, was used. Kuder and Richardson (1937) developed the KR-20 formula based on the assumption that each substance has the same medium and variance (Atılgan et al. 2009). In the present research, the internal consistency analysis was performed to determine the reliability of the achievement test, and the KR-20 value of the pilot test was found to be reliable as .70. According to this result, it can be claimed that the test is good discriminating and moderately difficult and reliable (Kan, 2008;Küçükahmet, 2002;Tekin, 2004).

SLMS Test:
To determine the motivation levels of students related to science learning, the SLMS test developed by Dede and Yaman (2008) was used. The researchers applied the preliminary applications of the motivation scale on 421 students. To determine the validity of the scale consisting of 23 items, the exploratory factor analysis was used, and it was found to be divided into five factors, explaining 47% the total variance of the scale, as, "Research for motivation", "Performance for motivation", "Communication for motivation", "Motivation for cooperative learning", "Motivation for participation". The variance values explained related to the factors of the scale were found to be 21.37 % for the first factor, 7.88 % for the second, 7.27 % for the third, 5.88 for the fourth, and 4.76 for the fifth. Also, Cronbach's alpha value of this scale, which was in Likert type, was found to be .80 (Dede & Yaman, 2008).

Qualitative interviews:
To support the study with student opinions and interpretations, the unstructured interview, which is one of the qualitative research methods, was preferred. Unstructured interviews provide the researcher with a great deal of freedom to ask related items. The questions and their order are not fixed, they can be changed during the interview. In this method, it is aimed to collect rich and sufficient information (Büyüköztürk, 2013). The unstructured interview consists of open-ended and flexible questions, and it is commonly in a chat-style (Merriam, 2013). Also, these chat-style interviews help the researcher to adapt to the situation and individual differences being interviewed (Yıldırım & Şimşek, 2013). The unstructured interview was preferred because it was thought to contribute to the research within the framework of the mentioned characteristics. Totally 11 students, with low science achievement (n=3), with moderate science achievement (n=5) and with high science achievement (n=3), were selected based on volunteering for interview purposes. Necessary approvals were obtained from the parents of the students determined following the decision of the ethics committee of human studies. Firstly, the purpose of the study was explained to the students and it was stated to the students that grading was not applied for evaluation and their names would be kept secret. Also, before the interview, the students were reminded of basic concepts related to the research and asked to write their thoughts. In this way, it was tried to prevent the students from being forced, excited and getting out of the subject while expressing their thoughts during the interview. The interviews were applied to the experimental group. In one lesson (40 minutes), students' answers were recorded directly by the researcher with a paper and a pen. Each student was individually interviewed and being affected by each other was prevented. Interviews were repeated several times and statements that were regarded as significant during the interview were identified. Also, behaviors that can be directed to students were avoided and their opinions were recorded without changing. The students were coded and numbered without giving their names.

Data Collection
The SIAT and SLMS tests were administered to the experimental and control groups as pre-test at the beginning of the research process. Then, for 3 weeks, the experimental groups were taught with case-oriented station technique and the control groups were taught within the framework of the program prepared by the MoNE. The SIAT and MS SLMS SL tests were applied to the students as posttest at the end of the lessons. For the case-oriented station technique, 4 stations were created for 2hour courses, taking into account the gains, physical characteristics and availability of the classes. Students were distributed heterogeneously to the stations and elected a group president for each station. The students were informed about the case study and station technique. For the case study, internet news related to the gain was found, the questions related to the news were created, and different station activities (posters, experiments, pictures, etc.) were prepared with 12 sample cases to present at each station, which also facilitated understanding of the sample event. At the same time, as the cases contained the necessary information for the subjects to be reinforced at the stations, the relevant information did not have to be included in the stations. Case studies and worksheets were completed with instructions and names were given to each station. The necessary material list was prepared and provided for the activities to be held at the stations. Under the guidance of the researcher, the groups worked at each station for 15 minutes and then moved to the other stations after the duration. After reading the cases (newspaper news) to the stations, the groups answered questions about the cases and carried out activities on the same topic. At the end of the events, the resulting products were exhibited and interpreted.

Data Analysis
The results of the SIAT and SLMS tests, administered to the experimental and control groups as te pre-test and post-test at the beginning of the research process, were analyzed with the statistical programs. Before the analysis process, the normality of distribution of pre-test and post-test scores of SIAT and SLMS was determined. The Kolmogorov-Smirnov normality test is recommended for the samples larger than 50 (Büyüköztürk, 2013). As the sample of the research was larger than 50, the Kolmogorov-Smirnov test was applied. The analysis results are presented in Table 1. As the analysis results in Table 1 are taken into consideration, it is seen that the pre-test and posttest scores distribute normally (p>.05). For this reason, the t-test, which is among the parametric tests, was applied in the analysis of the data.

Sub-dimensions
In the analysis of qualitative data, content analysis technique was used, and the data were analyzed by creating codes and categories. 4 categories with 15 codes were created for student views on socioscientific issues, 4 categories with 22 codes for opinions on station technique, and 2 categories with 11 codes for opinions on case study method. Besides, the data were coded under the themes determined by another expert and according to the results, the items with "Consensus" and "Dissidence" were determined. The codes gathered were analyzed with the Reliability= (Consensus/ Consensus+ Dissidence) formula suggested by Miles and Huberman (1994). The percentage of consensus was found to be reliable, with a percentage of 81%, as it is above 70% (Miles & Huberman, 1994). Also, the validity was tried to be provided by a detailed description of the method and process, giving the findings with direct quotations and expert examination in the research.

Findings
The findings related to the SIAT and SLMS tests, prepared for this research, and interviews held are presented in this section.

Findings Obtained from the SIAT Test
The SIAT was applied to the experimental and control groups before the issues stated in the research, the findings of the independent samples t-test are presented in Table 2. As a result of the independent samples t test, there was no significant difference (p> .05) between the control group pretest mean score ( ̅ = 8.69) and the experimental group pretest mean score ( ̅ =9.50). The dependent samples t-test was applied to compare the SIAT averages of the pre-test and post-test of the students in the experimental and control groups. The results are presented in Table 3. A significant difference (t=-8.28 p<.05) was found between the SIAT average ( ̅ pre-test =8.51) before beginning the issues and the post-test SIAT average after finishing the issues ( ̅ post-test ==10.11) in the control group. Similarly, in the experimental group, significant difference (t=-20.69 p<0.05) was found between the pre-test SIAT average ( ̅ pre-test =9.50) and post-test SIAT average ( ̅ post-test =14.72). The independent samples t-test was performed between the post-test averages of the groups to determine which methods are more effective in the control and experimental groups. The results are presented in Table 4. In the independent samples t-test, a significant difference (t=-6.61 p<.05) was found between the control group post-test average (X=10.11) and experimental group post-test average (X=14.72), in favor of the experimental group.

Findings Obtained from the SLMS
In the research, before starting the issues stated in the research, the SLMS was applied to the experimental and control groups. The independent-samples t-test findings gathered with the SLMS are presented in Table 5. No statistically meaningful difference was observed although the pre-test SLMS average of the independent samples t-test of the control group ( ̅ =95.36) was higher than the pre-test SLMS average of the independent samples t-test of the experimental group ( ̅ =93.38). The dependent samples t-test was applied to compare the pre-test and post-test of SLMS averages of students in the experimental and control groups. The results are presented in Table 6. In the dependent samples t-test results, no statistical difference was found between the pre-test average ( ̅ =95.31) and post-test average ( ̅ =95.14) of the students in the control group. In the dependent samples t-test results, a significant difference (t=2.34 p<.05) was seen in favor of the posttest average between the pre-test average ( ̅ =93.38) and the post-test average ( ̅ =98.08) of the students in the experimental group.
To compare the effect of the methods used in the control and experimental groups on the motivation for learning science, independent samples t-test was performed between the post-test averages of the groups. The results are presented in Table 7. In the independent samples t-test, no significant difference (t=-1.10 p>.05) was encountered although the post-test average of the experimental group ( ̅ =98.08) was higher than that of the control group ( ̅ =95.61).

Findings Gathered from the Qualitative Data
4 categories and 15 coded were created related to student opinions about the socio-scientific issues.
In issue category, there are topics that the students mentioned during the interview. In this category, there are 3 codes including global warming, sustainable development and biotechnology. 7 students (63.00%) expressed their opinions related to global warming, 3 (27.00%) to sustainable development and 9 (81.00%) to biotechnology. The student coded as S 4 stated: "…glaciers melt as a result of global warming and endanger the lives of the animals living there. To prevent this is in our hands". The student coded as S 9 claimed: "…we learned about the benefits, harms, and uses of biotechnology. For example, the prolonged shelf life of foods is useful, can be given as the treatment of diseases." In the cognitive category, 5 codes were created as information, researching, different opinions, beneficial and important. 3 students (27.00%) expressed their opinions about information, 1 (9.00%) researching, 2 (18.00%) different opinions, 4 (36.00%) beneficial, 2 (18.00%) important. The student coded as S 1 stated: "…we talked about socio-scientific issues, exchanged ideas, I think it was very useful".
In affective category, there are 2 codes as engaging and fun. 2 students (18.00%) expressed their opinions about engaging and 2 students (18.00%) about fun. The student coded as S 11 claimed,"… The topics were interesting to me. I'm not bored because it's different".
In the suggestion category, there are 5 codes as social work, environmental protection, awareness raising, recycling and energy saving. 1 (9.00%) student expressed an opinion about social work, 4 (36.00%) environmental protection, 1 student (9.00%) awareness rising, 3 (27.00%) recycling and 3 students (27.00%) energy saving. 9.00 36.00 9.00 27.00 27.00 S 9 S 2 , S 4 , S 8 , S 10 S 9 S 3 , S 4 , S 6 S 4 , S 8 , S 11  2  3  3  1  5  1  1  3  3  1  2 18.00 27.00 27.00 9.00 45.00 9.00 9.00 27.00 27.00 9.00 18.00 S 1 , S 5 S 1 , S 3 , S 5 S 1 , S 8 , S 11 S 2 S 2 , S 4 , S 5 , S 7 , S 9 S 2 S 2 S 3 , S 7 , S 10 S 4 , S 7 , S 9 S 6 S 3 , S 9 Negative Interruption Joint decision Relocation 2 1 2 18.00 9.00 18.00 S 7 , S 10 S 3 S 3 , S 10 The student coded as S 6 stated: "…tree cutting can be reduced by recycling paper. If people throw one or a few used pieces of useless paper into recycling bins every day, half of the trees in our world will be saved.". S 9 claimed: "…I think socio-scientific issues should be explained in social areas outside the school. For example, the harms of global warming should be explained in conferences. Thus, people can work to save the lives of living things by applying what they have learned" 3 categories and 22 codes were created related to the opinions about the station technique.
Station category consists of the stations which the students admired most. In this category, there are 4 codes; experiment, design, poster and painting. 6 students (54.00%) claimed that they admired the experiment station, 3 students (27.00%) design, 1 student (9.00%) poster and 1 student (9.00%) painting. The student coded as S 8 stated: "…my favorite was an experiment. Because I like to learn by observing and researching things".
Positive category consists of positive expressions related to the station technique. In this category, there are 11 codes including permanent learning, information, useful, effective, group work, responsibility, group contribution, fun, sharing, different events, enjoyed. 2 students expressed opinion (18%) that it provided permanent learning, 3 students (27.00%) that it was informative technique, 3 students (27.00%) that the stations were useful in learning the issue, 1 (9.00%) that it provided effective learning, 5 students (45.00%) liked the group work in this technique most, 1 student (9.00%) that the station techniques provided responsibility, 1 student (9%) that everyone contributed to the group, 3 students (27.00%) that the station technique was fun, 3 students (27.00%) that it increased sharing in group, 1 student (9.00%) that different event performed in stations, 2 students (18.00%) enjoyed the station technique. The student coded as S 2 said: "…I like group work because it requires responsibility for me. If my friends contribute to the group, I would like to contribute. Also maybe I would not understand if the teacher taught me, but now, I do not forget the issues that came to mind for our work". S 2 also stated: "…Thanks to the stations, the subjects were better in my mind, the lesson was quicker, meaningful and fun." In negative category, there are negative expressions of the student that they do not like about the station technique. In this category, there are 3 codes; interruption, joint decision and relocation. 2 students (18%) expressed that they were disturbed by the transition from one station to another before the end, 1 student (9%) the s/he does not enjoy joint decisions because s/he wants to make individual decisions, 2 students (18%) that they found the continuous relocation struggling. The student coded as S 7 claimed: "…When I started a station, I would love to end up. But we've always moved." The student coded as S 3 stated: "…we made a group decision, but I love working one time, so my decisions don't need to be approved by others." Two categories of 11 codes were created for the opinions about the case study method. S 2 , S 3 , S 9 S 1 , S 3 S 2 , S 7 , S 9 , S 10 S 3 , S 10 S 2 , S 4 , S 7 , S 10 S 5 , S 6 Method category consists of student opinions related to the case study method. There are 5 codes; different opinions, group work, information, useful, decision making. 3 students (27.00%) claimed that different opinions were expressed thanks to this method, 5 students (45%) that it was fun to examine case studies with group work, 3 students (27.00%) that the method provided information, 2 students (18.00%) that useful works were conducted, 2 students (18.00%) that it was significant to make decision with this method. The student coded as S 4 stated: "…our friends in the group said different ideas. I like to hear everyone's thoughts." Case-study category consists of student opinions about the cases selected for the method. 3 students (27.00%) found the cases from newspaper news to be effective, 2 students (18.00%) stressed that they gained the information they had never heard before thanks to the case study. 4 students (36%) found it effective that the case studies consisted of daily events. 2 students (18.00%) expressed that the case study was guiding to answer to given questions, 4 students (36.00%) that the cases were interesting, 2 students (18.00%) that case studies provided awareness about the society. The student coded as S 3 stated: "…I've had information with the news I've never seen in newspaper news". Ö 7 claimed: "…There was interesting news seen in our daily lives. I wasn't distracted by the news as I found them interesting."

Conclusion Related to the Findings Gathered from the SIAT Test
Any significant difference was not observed in the SIAT pre-test results administered to the experimental and control groups for the sub-problem "Does teaching the socio-scientific issues, (GW-SD-BT) in 8th class with the case-oriented station technique have any effect on the academic achievement of the students?" This shows that the readiness and knowledge levels of the students are close to each other. Similarly, in the studies by Albayrak (2016) and Aydemir (2010), it was noticed that there was no significant difference between the pre-test achievement score averages of the groups.
Meaningful difference encountered in favor of the post-test in the experimental and control groups according to the dependent samples t-test results between the pre-test and post-test SIAT averages shows that both the program approved by the MoNE and case-oriented station technique were effective in teaching the socio-scientific issues (GW-SD and BT) in 8th class. In studies in which the case study method (İbrahimoğlu, 2010;Sancar, 2010) and the station technique (Albayrak, 2016;Çakmak, 2018;Koca, 2018;Yüksel, 2017) were used, it is seen that similar results with the present study were reached.
Independent samples t-test results between the post-test averages of the groups to determine which methods are more effective in the control and experimental groups demonstrated that the caseoriented station technique used in the study increased the academic achievement in the 8th class socioscientific issues (GW-SD and BT) compared with the current program of the MoNE, and was more effective in teaching. The present study and other studies supported that the case study method has a positive effect on the academic achievement of the students (Adalı, 2005;Çakır, 2002;Herreid, 1994;İbrahimoğlu, 2010;Pehlivanlar, 2005;Stepien & Gallager, 1993;Uğur, 2007;Yalçınkaya, 2010). The results gathered from the relevant researches demonstrate similarity with this study. In the study by İbrahimoğlu (2010), it was found that using the case study method in social studies lesson increased academic achievement. Yalçınkaya (2010) found that the case-oriented learning model is an effective method to eliminate students' misconceptions compared to the traditional method. As the literature was reviewed, it was seen that the activities with the station technique has a positive effect on academic achievement and teaching (Albayrak, 2016;Arslan, 2017;Aydemir, 2010;Avcı, 2015;Benek, 2012;Çakmak, 2018;Demir, 2008;Demirörs, 2007;Erdağı, 2014;Farkas, 2002;Frailing, 1982;Güneş, 2009;Kara Ekemen, 2017;Koca, 2018;Mergen, 2011;Robert, 1999;Yüksel, 2017).

Conclusion Related to the Findings Obtained from the SLMS Scale
Any significant difference was not seen (p>.05) between the groups according to the SLMS pre-test results applied to the experimental and control groups in the t-test, in which the pre-test averages of the groups were compared, in terms of the sub-problem "Does teaching the socio-scientific issues, (GW-SD-BT) in 8th class with the case-oriented station technique have any effect on the motivations of the students?" According to the dependent samples t-test results in which the SLMS pre-test and post-test scores of the students in the control and experimental groups a meaningful difference was found in the experimental group (p<.05) while no significant difference was observed among the scores of the students in the control group (p>.05). This shows that the activities and collaboration with the methods and techniques used in the course increase the motivation of the experimental group students to learn science lesson. As the literature was reviewed, similar results were encountered (Akıllı et al., 2017;Aytekin, 2018;Eilks, 2002;İnel, 2012;Oksal, 2014;Özaydın Özkara, 2016;Yakar, 2017;Yıldıran Sönmez, 2015). Eilks (2002) concluded that the station technique applied in chemistry class increased the motivation of the students. He stated that this situation affected learning through cooperation. Yakar (2017) found that the experimental group students had higher motivation in his thesis in which he used the Socratic questioning technique for socio-scientific issues. Yıldıran Sönmez (2015) stated in the thesis where a case-oriented learning method was applied, that the method had a positive effect on motivation in favor of the experimental group for learning chemistry lesson.
The post-test averages of the independent samples t-test between groups applied in order to compare the effect of the methods in the control and experimental groups on the motivation toward science learning demonstrated that no statistically meaningful difference occurred (p>.05) even if the post-test average of the experimental group ( ̅ =98.08) was more than that of the control group (X=95.61). Although the method applied positively affected the motivation of students to learn science, it can be claimed that this difference was not meaningful. This is thought to be due to the short duration of the study. Besides, some researchers attributed the lack of a significant difference between motivation scores for learning to the high or low student and school achievement, crowded classes, and poor socioeconomic status (Aydoğdu, 2017;Karcı, 2018;Konu 2017;Yalçınkaya, 2010).

Conclusion Related to the Findings Gathered from the Qualitative Data
Student opinions on the interviews held to find the answer to the sub-problem "What are the students' opinions after the application of teaching the socio-scientific issues, (GW-SD-BT) in 8th class with the case-oriented station technique?" were analyzed by grouping into codes and categories as socio-scientific issues, case study method and station technique. As the findings gathered from the student opinions related to the SSIs, it is seen that the students expressed opinions related to the issues of global warming, sustainable development, and biotechnology, made suggestions, interpreted about their uses and harms by giving examples. So, the SSIs take the attention of the students and develop critical thinking and decision-making skills. In parallel to this result, similar results were encountered in the relevant literature. Zeidler and Nichols (2009) pointed out in their study that the SSIs teaching motivates students for scientific issues, but also contributed to inter-disciplinary connections such as critical thinking, reading skills, and being democratic, tolerant and caring about human values. Similarly, Dolan et. al. (2009) stressed in their research that the SSIs offer a multidimensional approach, such as understanding and discussing the importance of science for society, social conscience, and not only scientific content on a subject, but also in daily life. Talens (2016) stated in his study that the SSIs teaching is important for students to connect with the real-life, examine the positive and negative aspects of the chosen subject and gain experience for the students. Related to this topic, taking attention to social concerns and their effects, access to information through scientific ideas and practices, criticism, sharing information, use of information and communication technology, students' use of experiences and social interaction were important factors in the SSI model developed by Friedrichsen, Sadler, Graham and Brown (2016). Babacan (2017) stated in his study that activities carried out with socio-scientific issues improved students' critical thinking skills and students produced answers that are more qualified after activities.
During the interviews, the students made suggestions about energy saving, recycling and environmental protection based on the subjects they saw in the activities and stated that social studies should be done on these issues. Taşpınar (2011), in his socio-scientific discussion supported by health, observed that students were more participant in events they encountered in their daily lives. Yakar (2017) states in his thesis on socio-scientific issues that SSIs are considered significant by students in terms of being a tool for learning situations and events related to people, society, world, environment. Also, it was concluded that the students enjoyed, loved and wondered while discussing and researching these subjects. Therefore, the researcher stated that SSIs are important issues to be learned from within life. Similarly, Pelch and McConnel (2017) emphasized that the continuous use of SSIs in the course has a positive effect on students' interest and attitude towards science.
In the interviews, the students found that the news given as a case was open to discussion, which helped to create different ideas, and that they were important, useful, interesting and fun. Sadler (2011) stressed that it is important to use the media in SSI teaching to enable students to relate what they have learned to everyday life and to use technology to enrich learning experiences in the classroom. As it is supported in the literature, in the present study, it is seen that the case study method chosen for teaching socio-scientific issues is appropriate, effective and useful for teaching these issues.
When the findings obtained from the students' opinions about the case study method with socioscientific issue content are examined, the students mentioned the case studies in their activities as an interesting and useful method in-group news, which are frequently encountered in daily life, interesting, help to produce different ideas and make decisions. It is seen that studies in the literature are in parallel with the present study. İbrahimoğlu (2010) revealed in his thesis that students stated that the course was enjoyable with the case study method, as the effective participation was ensured and examples from daily life were carried to the classroom. Özkan (2010), in the interview with teachers about the purpose of using the case study in the classroom, found the results of reconciling the course with the students' lives, providing persistent learning by understanding and participating in the course, providing the students to try to solve and confront the problems and concretize the event. In other studies, similar results are encountered (Ada, Baysal & Kadıoğlu, 2009;Aydemir, 2010;Herreid, 1994;Pehlivanlar, 2005;Uğur, 2007;Ütkür, 2016).
During the interviews about station technique consisting of socio-scientific issues, the students found the activities to be permanent, useful and fun. Also, most of the students stated that they enjoyed group work, sharing, taking responsibility and contributing. Frutani (2007) found in the research that students love learning stations and develop responsibility and cooperation. Porter (2004) pointed out that students admired the station technique in mathematics lesson, they enjoyed during learning in the lesson.
During the research process, in the interviews related to the socio-scientific case-oriented station technique, some students emphasized the unfinished station activities and the continuous relocation as a negative situation. Besides, in the long-term applications, students were observed to move away from their goals. In parallel to this result, Eilks (2002) stated that the station technique may be difficult for students in the first application and that students may move away from their original goals in the longterm practice. Avcı (2015) stated in his research that some students found activities about station technique too boring and could not train time.
According to the results reached considering the research findings, case-oriented station technique seems to be appropriate, effective and useful for teaching socio-scientific issues. Also, the present study differs from many studies on socio-scientific issues in terms of the existence of two different methods and techniques and the use of qualitative and quantitative studies together.

Recommendations
In this section, according to the results of the study, recommendations for the effective use of caseoriented station technique are given to researchers and practitioners.
 As the literature is reviewed, it is seen that there are few studies on teaching socio-scientific issues in the classroom. The case-oriented station technique is an effective and useful study in the teaching of socio-scientific issues and is one of the few studies conducted. So, further research on the teaching of socio-scientific issues in the classroom is recommended.
 Case-oriented station technique can be applied to other issues rather than those in this research; Global Warming, Sustainable Development and Biotechnology.
 In the research, it was observed that the students discussed and produced different ideas about socio-scientific issues and made suggestions for social problems. In this context, more attention should be paid to socio-scientific issues in terms of raising individuals who think, criticize and produce ideas in the future.
 In the study, it was seen that the socio-scientific issues mentioned in the newspaper news attracted the attention of the students. Therefore, students should be encouraged to read newspapers, articles and journals containing socio-scientific issues.
 This research was limited to 8th class students. The case-oriented station technique can be repeated with students at different class levels.
 The research was carried out in the science course. It is thought to be beneficial to apply it in different courses.
 This study is limited to a specific sample and is recommended to be applied in larger samples.
 The number of stations that will appeal to each student in the classroom can be increased by investigating the interests and abilities of the students in different studies related to the station technique.
 To implement these and similar activities in crowded classrooms, teachers should make a detailed plan in advance and take precautions against negative situations in cooperation with the students.