  Consider a set of order statistics that arise from sorting samples from two
different populations, each with their own, possibly different distribution
function. The probability that these order statistics fall in disjoint, ordered
intervals, and that of the smallest statistics, a certain number come from the
first populations, are given in terms of the two distribution functions. The
result is applied to computing the joint probability of the number of
rejections and the number of false rejections for the Benjamini-Hochberg false
discovery rate procedure.
