The Influence of the Mastery of Function Words on Students’ Reading Ability

This study is an ex-post facto research which aims to find out the influence of the mastery of function words on reading ability of the seventh grade students of secondary school and to find out how the reading ability between students with adequate function words’ mastery and students with inadequate function words’ mastery is. The samples used in this research were two groups of students who have adequate and inadequate function words’ mastery. Each group consists of 30 students that is chosen by using stratified random sampling. In analysing the data, researcher used Independent Sample t-Test. The result shows that the mastery of function words significantly influences students’ reading ability. It is found that there is significant difference of students’ reading ability between students with adequate mastery in function words with those having inadequate mastery in function words. It is found that students with adequate function words’ mastery have better and higher ability in reading than students having inadequate function words’ mastery.


INTRODUCTION
"Words in language is traditionally divided into two major groups on the basis of their grammatical behavior and main functions: content words and function words" (Biber et al, 1999). Content words are classified "open-class" words which mean this class of words can be frequently added by new words. Meanwhile, function words are classified as "close-class" words. "Function words do not have clear lexical meaning or obvious concepts related to them. There are approximately 500 or so function words in English, and, of the 100 most common words in English, most are function words" (Smith & Witten, 1993).
In English, function words can be classified as grammar and vocabulary. In English grammar, function words have roles to merge each content word. Meanwhile, if it is compared with content words, function words can be classified as vocabulary (Fries, 1974). According to Biber et al. (1999), function words in English include parts of speech such as "determiners, pronouns, primary auxiliaries, modal auxiliaries, prepositions, adverbial particles, coordinating conjunctions and subordinating conjunctions, wh-words, existential there, the negator no, the infinitive marker to, and numerals (including ordinals and cardinals)." lity in reading, this research tries to find out the influence of the mastery of function words on reading ability. This study aims (1) to show how the mastery of function words influences reading ability of the seventh grade students of secondary school. Moreover, the objective of this study is (2) to know how the reading ability of students with adequate function words mastery compared with the students with inadequate function words mastery is.
The function words mentioned above are discussed in this research, but those function words are still classified into more detailed types. Nonetheless, function words which surely used in this research are the function words which appeared in some texts and textbooks of the 7th grade of junior high school. Those function words are prepositions, determiners (include articles and quantifiers), pronouns (subjective pronouns, objective pronouns, possessive pronouns, possessive adjectives), conjunctions (coordinate conjunction only), and auxiliaries.
The reading texts used in this research also adjusted to the learning materials in the seventh grade of junior high school. Materials tested in this test consist of reading texts which have been learned in the seventh grade of Junior High School both in the first semester and the second semester. Those texts are about greetings, identity, introductory texts, descriptive texts, and short functional texts such as, invitation letter and announcement texts.

METHODS
This research is a quantitative research. Quantitative approach in this study is aimed to test the influence of the mastery of function words variable and reading ability variable. In the field of the study, this research is an ex-post facto research. Ex-post facto research is a research on variables that occur before the research was conducted (Arikunto, 2013). In other words, this particular text" (Urquhart & Weir, 1998).
The understanding of vocabulary and grammar may effect students' ability in reading. "Vocabulary knowledge has long been recognized as having a close relationship with the development of reading ability" (Grabe, 2009a). Meanwhile, "grammatical knowledge is important to the comprehension of texts" (Givón, 1995).
Some researchers found that grammar has roles in reading skill. Andini et al. (2014) found that there were correlation between the mastery of grammar and students' reading comprehension. It was shown that there was a positive correlation between them. Also, the correlation between students' grammar mastery and reading comprehension is significant. Karyadi (2016) found that, "there is a correlation between mastery of grammar and reading comprehension achievement in SMK SMART Bekasi." The correlation between them are positive and significant. Moreover, Negara (2016) found that, "there is positive correlation between grammar mastery and their ability in reading comprehension of first semester students in STIE Pontianak in Academic Year 2016/2017". The results showed that the correlation between the mastery of grammar and reading comprehension ability is significant.
Vocabulary also has roles in reading ability. Ratnawati (2006) found that, "there is significant correlation between vocabulary mastery and reading comprehension of the seventh grade students of SMP N 13 Semarang in academic year 2005/2006." Meylana (2019) found that there are some factors which affected students in their reading comprehension. Those factors are the lack of vocabulary, lack of using reading strategies and facing serious problem because of grammar. It means both grammar and vocabulary affect students' reading ability.
Studies about the influence of both grammar and vocabulary on reading are also found. Sasmita (2012) found out the students' problem in reading comprehension of English text. The research finding showed that, "the factors that make students have difficulties in understanding English reading text is grammar knowledge and lack of vocabulary." Furthermore, Dini (2015) found that, "there is significant and positive correlation between students' grammar mastery and their reading ability. Also, this study found that there is significant correlation between students' vocabulary mastery and their reading ability." From the previous studies above, function words which classified as grammar and vocabulary might also effect students' reading ability. Since function words might effect students' abi-research is related to existed condition or related to variables (the Mastery of Function Words and Reading Ability), which have been possessed by the students. Therefore, there is no treatment (teaching) to the students because this is not an experimental research.
The subject of this study is the seventh grade students of SMP Negeri 1 Semarang Academic Year 2019/2020. This study has two groups of samples, each consisting of 30 junior high school students in grade seven. The First Group is a group of students who have Adequate Mastery of Function Words. Meanwhile, the Second Group is a group of students who have Inadequate Mastery of Function Words. Then, the independent variable of this research is the students' mastery of function words, while the dependent variable is the students' reading ability. Instruments used to collect the data are two sets of tests, those are, a set of test on Function Words and a set of test on Reading Ability. In this research, the two instruments are constructed in the form of objective test, that is multiple choice test. There are four options in each item of the tests. Each test consists of 50 items. Before taking the data, the writer conducted a try-out test on the instruments. This try-out test was conducted to test the validity and the reliability of the instruments (Function Words Test and Reading Ability Test).
The technique of sampling used in this research is stratified random sampling. The sample was grouped into two levels by using a set of test on Function Words. The population were given function words tests and then the students' scores were ranked from the highest to the lowest. From the ranking, the students' scores were made two level of gradation: top level of gradation and bottom level of gradation. The two groups of samples (the adequate and inadequate group) was taken at random from the top level of gradation and from the bottom level of gradation using stratified random sampling. Each group of samples consisted of 30 students. Those groups are the First Group (Students with Adequate Function Words' Mastery) and the Second Group (Students with Inadequate Function Words' Mastery).
The data of this research is the score of students' reading ability test. This data was obtained by giving the reading test to both groups of samples, the First Group and the Second Group. The data was analyzed by using inferential statistics. The inferential statistics formula applied in this analysis is the Independent Sample t-Test. Before testing the data using t-test, there were prerequisite test which must be conducted. Some techni-ques in statistics need requirements (Arikunto, 2013). Those requirements are requirements of normality and homogeneity. "Normality test is used to measure whether the data are normally distributed or not. Normality test is one of the most common assumption made in the development and use of statistical procedures" (Thode, 2002). This research used Liliefors Formula to test the normality of the data. The Liliefors Test in this research was tested by using SPSS 22 Version. The Homogeneity Test was also conducted. This research used Levene formula to test the homogeneity of the data. The Homogeneity Test in this research was computed by using SPSS 22 Version.

RESULT AND DISCUSSION
The subject of this study is the seventh grade students of SMP Negeri 1 Semarang. The process of data collection was conducted by online due to Covid-19. The samples of this research are two groups of students (Group I and Group II), each group consists of 30 students. The First Group (Group I) are students having adequate mastery of Function Words. Meanwhile, the Second Group (Group II) are students who have inadequate mastery of Function Words. The data used in this research is the students' scores of Reading Ability Tests from the First Group and the Second Group. The Table 1 is the summary of the data description from the First Group and the Second Group which consist of number of sample, range of score, sum of score, mean, median, mode, and standard deviation. From the Table 1, it is known that the number of each group is the same, that is 30. Then, the range score from the First Group and the Second Group are different. The lowest score in the First Group is 90, while the highest score is 98. Meanwhile, the lowest score in the Second Group is 74 and the highest score is 90. From the range of score, it is known that the Second Group has more range of scores. Then, from table 1, it can be seen that the sum of score of First Group is higher than the sum of score of Second Group. Same as the sum of score, the mean of the First Group is also higher than the mean of the Second Group. The mode of the First Group is 94, while the score which frequently appears in the Second Group is 80. The standard deviation of the First Group is 2.753 and the standard deviation of the Second Group is 4.563. One of the factors which affects the differences of the standard deviation from each group is the range of score in each group.

Prerequisite Test
After collecting the data, there are tests which must be conducted. As stated before, the inferencial statistics, that is Independent Sample t-test is applied. However, before testing the data using the t-test, there were some prerequisite tests which must be conducted. According to Arikunto (2013), some techniques in statistics need requirements. Those requirements are requirements of normality and homogeneity. Therefore, in this research, there were two prerequisite tests which were conducted, those are Normality Test and Homogeneity Test.

Normality Test
"Normality test is used to measure whether the data has a normal distribution or not. Normality test is one of the most common assumption made in the development and use of statisctical procedures" (Thode, 2002, p.1). In this research, the data which were tested using Lilliefors are two groups of data. Those two groups are the data on Reading Ability Test of the First Group (students with adequate Function Words' Mastery) and the data on Reading Ability Test of the Second Group (students with inadequate Function Words' Mastery. Each group of the data consists of 30 data. This research used Lilliefors formula to test the normality of the data. This normality test is calculated by using SPSS 22 Version. The criteria of the Liliefors Test is: reject the hypothesis that the population has normal distribution if the L 0 obtained from observational data exceeds L from the list (L table ). In other cases, the hypothesis is accepted. (Sudjana, 2005, p. 451) From the statement above, it is known that the population has a normal distribution if L 0 < L table . Meanwhile, in SPSS, residuals has a normal distribution if they have a significance value of more than 0,05 (Ghozali, 2013, 160). Here is the results of Normality Test. The results of the normality test using the Lilliefors method showed that the significance results (Sig.) from the normality test in both groups are 0.120 and 0.165, where the results were more than the significance level of 0.05 (0.120 > 0.05 and 0.165 > 0.05). From the normality computation, it can be drawn a conclusion that the population from the First Group and the Second Group have a normal distribution.

Homogeneity Test
In addition to the normality test, a homogeneity test must also be carried out before conducting the t-test. Homogeneity test is used to find out whether the two groups of samples have homogeneous variances or not. This research used Levene formula to test the homogeneity of the data. The Homogeneity Test in this research was calculated by using SPSS 22 version. This is the criteria of Homogeneity Test in SPSS: If the significance value of the test < 0.05, then it can be said that the variance of two or more data population groups are not the same (not homogeneous). If the significance value of the test ≥ 0,05, then it can be said that the variance of two or more data population groups are the same (homogeneous) (Uyanto, 2006). The Table  3 is the calculation of Homogeneity Test.
From Table 3, it is shown that the significance value (Sig.) in Levene's Test for Equality of Variances is 0.027, which is lower than 0.05 (0.027 < 0.05). Based on the criteria, if the significance value of the test < 0.05, it can be said that the variance of two data population groups are not the same or not homogeneous. In this case, the data from the First Group and the Second Group are not homogeneous because they are from different strata. The First Group is students having adequate function words' mastery, while the Second Group is studens having inadequate function words' mastery. Then, the scores of students' reading ability are different. From the summary of data description, the mean of the First Group is higher than the mean of the

Reading Ability
Equal variances assumed 0.027 Equal variances not assumed Second Group. Eventhough the data are not homogeneous, the t-test is still possible to be applied. In this case, the significance value applied in the Levene's Test for Equality of Variances is the equal variances not assumed.
Inhomogeneous data means that the variances are unequal. According to Weiss (2012), if the data are homogeneous, inferencial statistics for two population means using independent samples (t-test) are conducted by interpreting the standard deviations assumed equal. In other words, the table which is interpreted in the SPSS is the equal variances assumed. Meanwhile, if the data are not homogeneous, the table which is interpreted in the SPSS is the equal variances not assumed. In this research, the table of equal variances not assumed is used to interpret the results of the homogeneity test. Furthermore, this table of equal variances not assumed also used to interpret the result of the t-test.

Data Analysis
In this research, the data was analyzed using t-test. The t-test is used to test whether there is significant difference between the mean of the first data and the mean of the second data. If reading ability of the first group is significantly different from the second group, it can be concluded that function words give significant contribution or significant effect to reading ability.
The data in this research was specifically analyzed by using Independent Sample t-Test. It is because the data were taken from two different group of samples. The data analysis in this research was aimed to test the research hypothesis. The t-test formula was applied in order to test whether there is a significant difference between the Reading Ability Score of the First Group and the Second Group. If the result of the t-test is significant, it means that there is a positive influence of function words' mastery on students' reading ability.
The criteria of this test is: The null hypothesis is rejected if the Significance Value is lower than 0,05. The null hypothesis here is there is no positive influence of function words' mastery on students' reading ability. Based on the computation by using SPSS 22 version, the results of the t-test can be described as the Table 4. From the test results described in the table above, it can be seen that the significance value of the t-test is lower than 0.05 (0,00 < 0.05). The criteria of the testing is: The null hypothesis is rejected when the significance value is lower than 0,05. Since the null hypothesis (H0) is rejected, it can be concluded that the research hypothesis (Ha) is ACCEPTED. Because Ha is accepted, a general conclusion can be drawn that is the function words' mastery significantly influence the students' reading ability.
The data analysis in this research was conducted in order to test the first hypothesis which is related to the first research question and also to test the second hypothesis which is in line with the second research question. The followings are the explanation of the research questions.

The Influence of Function Words' Mastery on Reading Ability
The results of the t-test on Reading Ability is described on the Table 5. From the results of the data analysis, it is known that there is an influence of the mastery of function words on reading ability on the seventh grade students of secondary school. This influence is known from the calculation of the ttest, that is, there is significant difference between the mean of Reading Ability of the First Group (students with adequate function words mastery) and the Reading Ability of the Second Group (students with inadequate function words mastery) which is shown from the significance value from the equal variances not assumed. The significance value is lower than 0,05 (0,00 < 0,05).
For data analysis in this research, the t-test formula is applied. With the value of df is 58 (N1 + N2 -2) and the level of significance (alpha) is 0.05, from the t distribution table, it is found that the t table is 1.672, which is lower than the t value. In table 9, it is known that the t value is 12.332, which is higher than the t table . When the t value is  (t value > t table ), it can be concluded that there is a significant difference between the mean of the Reading Ability score of the First Group and the mean of the Second Group. In other words, because t value is higher than t table , it can be concluded that the null hypothesis (H 0 ) is RE-JECTED. Since the null hypothesis is rejected, it means that the first research hypothesis (Ha 1 ) is ACCEPTED. From the result of the testing, the final conclusion can be drawn that the first hypothesis: There will be a significant difference of students' reading ability between students with adequate mastery in function words with those having inadequate mastery in function words, is statistically proven. In other words, it can be concluded that there is a positive influence of function words mastery on reading ability.

The Reading Ability of Students with Adequate Function Words Mastery and Students with Inadequate Function Words Mastery
The following is the Table 6 of the mean from the First Group and the Second Group. From the results of the data analysis, it is known that the First Group has higher reading ability scores than the Second Group. It means that the students with adequate function words mastery have higher reading ability than the students with inadequate function words mastery. This statement is proven by the mean of the First Group and the Second Group. The mean of the First Group is 93.933, meanwhile the mean of the Second Group is 81.933. The means from both groups are known that they are significantly different after being analyzed using t-test.
The mean of each group has been computed statistically by using Independent Sample t-Test. The result is significant with the significance value is lower than 0.05, that is 0.00 (0.00 < 0.05). It means that the second hypothesis (Ha2) is AC-CEPTED. From the computation described in table above, it can be seen that the Reading Ability of the First Group (students having adequate function words mastery) is better or higher than the Second Group (students having inadequate function words mastery). It means that students with adequate function words' mastery have better and higher reading ability than the students with inadequate function words' mastery.
Function words are part of grammar and vocabulary. Function words are grammar when it is seen from its function in a sentence. Meanwhile, when it is compared with content words, function words are categorized as vocabulary. (Fries, 1974) Furthermore, the ability of reading cannot be separated from the mastery of both grammar and vocabulary. It means that the mastery of grammar and vocabulary influence someone's reading ability. The discussions of this research explain the influence of function words mastery on students' reading ability.
The first hypothesis of this research is formulated as follows: There is significant difference of students' reading ability between students with adequate mastery in function words with those having inadequate mastery in function words. If there is significant difference between them, it means that the mastery of function words influence students' reading ability. From the data analysis, it can be seen that the result of the t-test (t value ) is 12.332, that is higher than the t table (12.332 > 1.672). From SPSS 22 version, it is known that the significance value of the t-test is 0.00 (0.00 < 0.05). From the results described above, the result of the t-test is significant, so, there is a positive influence of the function words mastery on students' reading ability.
Based on the results which have been mentioned above, it shows that function words' mastery gives positive influence on reading ability of the seventh grade students of junior high school. Some previous studies discussed below also indicate the similar results. Ratnawati (2006) found that, "there is significant correlation between vocabulary mastery and reading comprehension of the seventh grade students of SMP N 13 Semarang in academic year 2005/2006" with the correlation coefficient 0.417, which is higher than the r table that is 0.220 (0.417 > 0.220). Simanjuntak et al (2015) found that, "there is significant direct effect students' vocabulary mastery to students' reading comprehension on the second grade students of SMA." The result of the study were the p-value = 0.000 < 0.05, which means that the effect is significant. From those previous studies, it can be said that the mastery of vocabulary influences the ability of reading. Function words as parts of vocabulary also give positive and significant influence on reading ability.
Some previous studies below are in line with this research. Andini et al (2014) found that, "there is positive correlation between grammar mastery and reading comprehension on the second grade students of SMP Negeri 12 Pekanba-ru" with the correlation value 0.441. Then, this study also found that the t value was higher than t table (2.9 > 2.724). According to them, it means that "there is significant correlation between grammar mastery and reading comprehension." Karyadi (2016) found that, "there is a correlation between mastery of grammar and reading comprehension achievement in SMK SMART Bekasi." It is found that with the level of significance 0.05 (5%) and df = 28, the r table is 0.374 and the r value is 1.023. It means that the r value > r table (1.023 > 0.374). Then, Negara (2016) also found that, "there is a positive correlation between grammar mastery and their ability in reading comprehension of first semester students in STIE Pontianak in Academic Year 2016/2017." The coefficient correlation of the result was 0,970, and it is higher than the r table .
The results also showed that the correlation between students' grammar mastery and the ability of reading comprehension is significant. It is showed by the t value which is higher than the t table (24.9 > 2.71). From the previous studies above, it is showed that vocabulary mastery give positive influence on reading ability. Those previous studies above are connected with the result of this research because function words are classified as vocabulary.
These previous studies below also support the results of the data analysis in this research. Dini (2015) found that, "there is positive correlation between students' grammar mastery and their reading ability at the first year of SMAN 1 Bandar Lampung" with the coefficient correlation is significant (0.6117259 > 0.393) at significance level 0,01. The study also found that, "there is significant correlation between students' vocabulary mastery and their ability in reading with the coefficient correlation 0.728 > 0.393 at significance level 0.01." It means both grammar and vocabulary mastery give positive influence to the ability of reading. Meylana (2019) found that vocabulary and grammar affected students in their reading comprehension. It is also found characteristics between students with excellent ability in reading and students with less ability. It is found that students with excellent ability were not facing serious problems because of grammar and do not have effort in using dictionary when they were facing difficult words. From this study, it is concluded that grammar and vocabulary give positive effect and influence on ability in reading.
From the previous studies mentioned above, this research is in line with them. The result of this research is also significant. The mastery of function words influences students' reading ability. The previous studies which have been mentioned, revelead that there was a significant influence between grammar and vocabulary mastery on reading ability. Function words which is classified as grammar and vocabulary also give significant influence on students' reading ability. As a result, it can be said that this study is in line with the previous studies mentioned above.
The second hypothesis of this study is stated as follows: Students with adequate function words mastery have higher and better reading ability than the students with inadequate function words mastery. The same as the first hypothesis, the second hypothesis is also accepted. The mean of the score of reading ability from students with adequate function words mastery is higher than the mean of reading ability from students with inadequate function words mastery, that is, 93.933 > 81.933 and the difference between two of them is significant. From the computation, it is known that students with adequate function words mastery have better reading ability than students with inadequate function words mastery.
The discussions on the result of data analysis show that the mastery of function words significantly influence students' reading ability. The result of this research indicates that the mastery of function words give positive influence and contribution to reading ability. Students with adequate function words mastery have higher and better reading ability than students with inadequate function words mastery.

CONCLUSION
The objectives of this study is to find out how the mastery of function words influences reading ability of the seventh grade students of secondary school. From the results of the data analysis, it is clear that there is significant difference in students' reading ability between students with adequate function words mastery (First Group) and the students with inadequate function words mastery (Second Group). In other words, it can be concluded that the mastery of function words influences students' reading ability. This study also aims to know how the reading ability of students with adequate function words mastery compared with students with inadequate function words mastery is. Based on the results of the data analysis, it is also known that the First Group has higher and better reading ability than the Second Group. Finally, it can be concluded that the students with adequate function words mastery have better and higher ability in reading than the students with inadequate function words mastery.
The suggestions of this research are intended to students, teachers and the further researchers. Suggestions for students are, it is necessary for students to learn function words in details. It is also necesarry for students to have adequate mastery on function words. Students ought to have curiosity and initiative to learn function words by themselves, because most of students' books do not provide materials about function words. Then, suggestions for teachers are English teachers are suggested to teach function words in the class once in a while. It can be taught integratedly through reading texts or any other teaching materials, and not in separated teaching materials. At last, suggestion for further researchers is it is hoped that there will be other researchers who discuss about the influence of function words in other language skills (listening, speaking, or writing) and involves different research subjects in other level of learners.