The upper and lower hinges are descriptive statistics of a set of data values, where is of the form with
, 1, 2, .... The hinges are obtained by ordering the data in increasing order , ..., , and writing them out
in the shape of a ``w'' as illustrated above. The values at the bottom legs are called the hinges and (and the
central peak is the Median). In this ordering,
See also H-Spread, Haberdasher's Problem, Median (Statistics), Order Statistic, Quartile, Trimean
Tukey, J. W. Explanatory Data Analysis. Reading, MA: Addison-Wesley, pp. 32-34, 1977.