The statistics
defined such that
where is a central
moment. These statistics generalize h-statistics
and were originally called "generalized
-statistics" (Tracy and Gupta 1974). The term "polyache"
was introduced by Rose and Smith (2002, p. 255) by way of analogy with the polykay statistic. Polyaches are commonly defined in terms
of power sums, for example
Polyaches can be computed using PolyH[r, s, ...
] in the Mathematica
application package mathStatica.