(a) The normal monthly precipitation (in inches) for August is listed for 20 different U.S. cities. Find the mean of the data.

(b) Calculate the standard deviation for the data

**Solution: **(a) The mean is computed as

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(b) By definition, the standard deviation is computed as

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## Stats Solution Summary

When using descriptive statistics, the mean is used as a measure of center, and the standard deviation is used as a measure of dispersion, which provide a rough view of the distributional properties of the population from which the sample was drawn.