Hinge

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 statistical median). In this ordering,

			(1)
			(2)
			(3)

For  of the form , the hinges  and  are identical to the quartiles  and . The difference  is called the H-spread.

REFERENCES:

Tukey, J. W. Exploratory Data Analysis. Reading, MA: Addison-Wesley, pp. 32-34, 1977.