Implementation of nonparametric multivariate statistics with S

Multivariate nonparametric statistical methods have not been widely used by psychologists. One reason for this may have been that the usual general-purpose packages do not provide easy implementation of these methods. In this article, we briefly describe the multivariate extensions of the sign, signed-rank, and rank-sum tests and use S, a programming environment for data analysis, to implement these statistical procedures. Three numerical examples are used to illustrate the flexibility and efficiency of these computations in S.