p.d.f.f of a real-valued r.v. X is said to be a Polya frequency function of

Application 3.1. (Sections 3.2(a) and 3.l(c) in Joag-Dev and Proschan, 1983). For 11 :S N, let X 1, ..• , X11 be a random sample without replacement from a finite population consisting of the values x 1, ••• , xN. Then X 1, ... , X 11 areNA, being a subset of X 1, .•• , X N' which has a permutation distribution and hence is NA. In particular, the multivariate hypergeometric distribution is NA.