# (a) The normal monthly precipitation (in inches)

(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.