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Unit 7: Numeracy skills

Averagescartoon pen

There are several ways of expressing an average. The most common way is called a mean . This is one value which is representative of all the numbers in a group. The mean is calculated by adding up all the numbers in a group, then dividing by how many numbers there are.

Example 1 Find the average, or mean, of the following numbers:

2 + 6 + 4 + 8 + 5 + 5 = 3 0 = 5
-------------------------------   ----    
          6               6    

Check your answer – in this case, most of the numbers are less than 5 but the very high value of 20 pulls the mean upwards, so the answer is sensible.

Example 3 In a test of numerical ability, students are tested in two groups. Which group has the higher average score?

Group A
Group B
3
7
15
6
8
10
9
11
12
19
13
20

3 + 1 5 + 8 + 9 + 1 2 + 1 3   7 + 6 + 1 0 + 1 1 + 1 9 + 20
-------------------------------------   ----------------------------------------
            6                             6              
                                                         
          = 6 0                         = 7 3            
            ----                           ----            
              6                             6            
                                                         
          = 1 0                         = 1 2 . 1 7      

Group B has the higher average score

Test yourself with the questions on the next page.


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SMILE - Numeracy skills by Tom Frank, Eric Williams and Clare Wright, University of Birmingham Careers Centre adapted by Marion Kelt Glasgow Caledonian University is licensed under a Creative Commons Attribution 3.0 Unported License.