X-Y S1/m+1/n 10. Assume that X -sample has m observations: X, X2,..., Xm, and Y -sample has n observations: Y,2,..., Y. Denote by X,Y, S, S% the means and the variances of X -sample and Y -sample, respectively. Let t = be the two-sample t- statistic, where (m1)S+(n1)S = m+n-2 m Show that the t statistic is a monotone function of the statistic Tx = X;, and conclude that the i=1 permutation tests based on t and TX are equivalent.