Measures of Center

The mean is also referred to as the AVERAGE and can be found by

Example: What is the average test score of a class with the following test scores?

80, 75, 79, 60, 85, 67, 64, 78, 82, 99

Solution:

adding all the numbers in your data
80 + 75 + 79 + 60 + 85 + 67 + 64 + 78 + 82 + 99 = 769
divide the sum of the numbers by the number of numbers
769 / 10 = 76.9

The median is the middle of the data and is found by

Note: If you find yourself with a data set with an even number of entries, add the two middle numbers and divide by two.

Example: What it is the median score of the following test scores?

80, 75, 79, 60, 85, 67, 64, 78, 82, 99

Solution:

sorting your numbers from least to greatest
60, 64, 67, 75, 78, 79, 80, 82, 85, 99
finding the middle value
60, 64, 67, 75, [78, 79,] 80, 82, 85, 99
Note: since we have an even number of entries, we will add the 2 numbers and then divide by two.
78 + 79 = 157 then
157/2 = 78.5