I have a question regarding the samr package. For a 2 class unpaired problem, with sample 1 of size N1 and sample 2 of size N2, samr computes at most (N1+N2)! permutations of the two samples (if the user-supplied parameter nperms allows it). However, there are only (N1+N2)/(N1!*N2!) DISTINCT permutations of the two samples, so it seems to me that only these distinct permutations should be taken into consideration. Of course, working with the (N1+N2)! permutations and working with the (N1+N2)/(N1!*N2!) distinct permutations will lead to the same correct result, but for a number of permutations smaller than (N1+N2)/(N1!*N2!), the result will generally be different. I would be very grateful if someone could provide me an explanation for the samr choice of the permutations. Thanks for your help, Isabelle ------------------------------------ Dr. Isabelle Rivals - Ma?tre de Conf?rences ?quipe de Statistique Appliqu?e - ESPCI 10 rue Vauquelin - 75231 PARIS Cedex 05 T?l : (00 33 1) 40 79 45 45 Fax : (00 33 1) 40 79 44 20