# Summary statistics

**Summary statistics**are needed when we have a set of observations which we want to summarize, and we want to communicate as much as possible as simply as possible. Statisticians commonly try to describe the observations in

- a measure of location, or central tendency, like the arithmetic mean
- a measure of statistical dispersion like the standard deviation
- a measure of the shape of the distribution like skewness or kurtosis

The Gini coefficient was originally developed to measure income inequality, but can be used for other purposes as well.

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