 For a dataset with "n" measurements, the set of all possible one- or two-element subsets of it has "n"("n" + 1)/2 elements.For each such subset, the mean is computed; finally, the median of these "n"("n" + 1)/2 averages is defined to be the Hodges–Lehmann estimator of location.The Hodges–Lehmann statistic also estimates the difference between two populations.