## Thinking Mathematically (6th Edition)

The arithmetic mean is found by adding all the data values in a set and dividing the sum by the number of data values. For example, the mean of the set: 3, 5, 4, 6 is found by adding the four values: 3 + 5 +4 + 6. The sum is 18. Then divide the sum of 18 by 4 (the number of values). $\frac{18}{4}$ = 4.5 (the mean of the data set).