Secondary data Data which has already been Data on the internet is secondary collected by someone else data Questionnaire An organised list of questions, often with options for answers Frequency Table A table that shows how often a particular item of data occurs. It often includes a tally column. Pictogram A diagram that shows data as a series of pictures. Bar chart A diagram that uses rectangles to represent frequency Pie chart A diagram that uses a circle to display data in proportion Line graph A graph that shows plotted points joined by straight lines Grouped data Data that is organised into class intervals Average A representative value for a set of The mode, median and mean data Mode The data value that occurs most Data: 3, 2, 5, 8, 5, 6, 2, 5 often Ordered: 2, 2, 3, 5, 5, 5, 6, 8 Median The middle when data are sorted into numerical order. If Mode = 5 there are two values in the middle, Median = (5 + 5) ÷ 2 = 5 the median is found by adding the two values and dividing by 2. … Mean = (2 + 2 + + 8) ÷ 8 Mean An average defined as the sum of all of the data values divided by the = 36 ÷ 8 = 4.5 number of data values Range The difference between the For the data above: highest and lowest values in a set of – = 8 2 = 6 data
Secondary data Data which has already been collected by someone else Data on the internet is secondary data Questionnaire An organised list of questions, often with options for answers Frequency Table A table that shows how often a particular item of data occurs. It often includes a tally column. Pictogram A diagram that shows data as a series of pictures. Bar chart A diagram that uses rectangles to represent frequency Pie chart A diagram that uses a circle to display data in proportion Line graph A graph that shows plotted points joined by straight lines Grouped data Data that is organised into class intervals Average A representative value for a set of data The mode, median and mean Mode The data value that occurs most often Data: 3, 2, 5, 8, 5, 6, 2, 5 Ordered: 2, 2, 3, 5, 5, 5, 6, 8 Mode = 5 Median = (5 + 5) ÷ 2 = 5 Mean = (2 + 2 + … + 8) ÷ 8 = 36 ÷ 8 = 4.5 Median The middle when data are sorted into numerical order. If there are two values in the middle, the median is found by adding the two values and dividing by 2. Mean An average defined as the sum of all of the data values divided by the number of data values Range The difference between the highest and lowest values in a set of data For the data above: = 8 – 2 = 6
Y7-Maths-Summer-2-Knowledge-Book.docx