Distribution of order statistics for exchangeable random variables

Let t1,. . .,tn be exchangeable random variables and suppose that ti:n represents the ith order statistic among t'is,i = 1,. . .,n. in this paper some expressions for the joint distribution of (t1:n,. . .,tn:n),marginal distribution of ti:n and the joint distribution of (tr:n,tk:n),1 ≤ r ≤ k ≤ n in terms of the joint distribution (or joint reliability) function of t'is are provided. using these and when [t1,. . .,tn] is a sequence of lifetimes,some expressions for the mean residual life functions of a n - k + 1-out-of-n system,hk n(t) = e(tk:n - t|t1:n > t) and mr,k n (t) = e(tk:n - t|tr:n > t),1≤ r ≤ k ≤ n in terms of the joint survival function of ti's are given. also,some examples are provided.