Revision - Statistical Data – Types of Graphs, Charts, Tables etc and what to look out for x Straight Line Graphs y = mx + c Pie Charts x Positive correlation Negative correlation No correlation Reading scatter graphs axis relationships y 28 122 x Facts Right angle = 90º 360º in a circle 5 3 From the above facts you will be able to find angle X 1 x Example Given y = 2x + 3, then plot table as shown below, Then do the graph shown above Typical Question might say 180 pupils in a school, and pie Chart consists of the following H = hockey F = football R = rugby N = netball Find the number of pupils that are playing football x Line Graphs Bar Chart Frequency Polygon 28 122 F N R H x y 1 2 3 -3 -2 -1 5 7 9 Frequency Table – Mid Values Estimating the Mean MEAN – (or average value) To find the mean first add all the individual numbers to find total and then divide by the number MODE – means most COMMON number MEDIAN – median is the middle number RANGE – means range from smallest to largest. To find the range take the smallest number from the largest Note – When finding mode ,median mean, and range ,first place numbers in ascending order if they are out of order. This will help clarify the solution to finding the values. Example - 2,3,4,5,5,7,8,9,11 MEAN (average value) is found by 2+ 3+4+5+5+7+8+ 9+11 = 54/9 = 6 MODE , most common value is 5, MEDIAN, middle value is 5 RANGE is between 2 and 11, therefore 11-2 = 9 10 20 2 7 1 3 6 9 30 40 4 Mean = 22 = 17 Key Code 2 +7 + 10 +11 +13 +17 + 21 + 21 + 22 + 26 + 29 + 32 + 33 + 33 +34 +41 = 352/16 Mean Mode is 21 (being the most common number) Median – Middle numbers are 21and 22 so median is 21.5 Range – 41 – 2 = 39 Stem / Leaf Table First find F – see first example to find F. 180 pupils means 360/180 gives 2º per pupil. Knowing F degrees, then you can work out number in F Height cm 0 <h ≤10 10 <h ≤20 20 <h ≤30 30 <h ≤40 40 <h ≤50 mid point 5 15 25 35 45 freq 2 4 8 1 Total 10 60 200 175 20 490 Totals Estimate the Mean by 1st find mid-values Add up frequency totals Mid- values x frequency to obtain total Add up all totals to obtain grand total Estimate Mean is 490 /20 = 24.5 Pictorial type, example display shown below