1 Average A single number which FAIRLY represents a group of other numbers. There are 3 types of average ( 3 different ways of working out an average number ) Menu

2 MEAN MEDIAN MODE Add up all the numbers and then divide by how many numbers there are. Put the numbers in order of size and then find the middle number. The number which appears most often. Menu

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4 MEAN Add up all of the numbers and then divide by how many numbers there are. Maths % English % History % French % Science-- 86 % = 65.8 % Menu

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6 Median (Put in order of size then find the middle number) Median = = 7.5 What if there is an even number of numbers ? Menu

7 Another Method of Locating The Median From Raw Data 2, 3, 3, 3, 5, 7, 8, 9, 9, 11, 12, 14, 14, 15, 18 Firstly count how many numbers there are in the list. 15 Then ADD 1 and divide by = 16 2 = 8 th number. Now count to it. Median = 9 What if there is an even number of numbers ? Menu

8 What if there is an even number of numbers ? 3, 5, 7, 11, 11, 13, 15, 21, 22, 23, 26, 30 Count how many numbers there are: 12 Then ADD 1 and divide by = 13 2 = 6.5 th number Between the 6 th & 7 th numbers Median = 14 Menu

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10 Mode (Modal Average) (The number/data which appears most often) Ex1) 3, 5, 2, 5, 3, 2, 4, 1, 3 Ex2) 12, 14, 14, 15, 11, 15, 16, 10 Ex3) 1, 0, 2, 1, 0,2, 3, 3 Mode = 3 Mode = 14 & 15 No Mode Menu Answers

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12 So anybody with a small range must be clever ? The RANGE Highest number – Lowest number What does it show ? Paul’s exam marks: Maths 89% Science 90% English 90% History 88% French 91% Range: = 3 David’s exam marks: Maths Science English History French Range = 3 ? ? ? ? ? 4% 3% 6% 5% 4% Small Range Consistent Reliable Predictable David must be clever ! Obviously not ! Menu

13 Jane’s exam marks: Maths 87% Science 55% History 32% French 74% English 45% Range = 87 – 32 = 55 Big Range Inconsistent Unreliable Unpredictable Menu