(i) If X1,..., Xm and Y1,..., Yn are samples from F(x) and G(y) = F(y − ), respectively, (F continuous), and D(1) < ··· < D(mn)

denote the ordered differences Yj − Xi , then P $

D(k) << D(mn+1−k)

%

= P0[k ≤ U ≤ mn − k], where U is the statistic defined in