Summary statistics

In descriptive statistics, summary statistics are used to summarize a set of observations, in order to communicate as much as possible as simply as possible. Statisticians commonly try to describe the observations in
 * 1) a measure of location, or central tendency, such as the arithmetic mean, median, mode, or interquartile mean
 * 2) a measure of statistical dispersion like the standard deviation, variance, range, or interquartile range, or absolute deviation.
 * 3) 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.