Geological applications of multi-response permutation procedures

The multi-purpose permutation procedures (MRPP) test statistic is designed to analyze multivariate data at the ordinal or higher levels. It is based on the weighted averages of symmetric distance functions over all paired objects withina priori disjoint groups of objects from a finite population of objects where each object's response is a point in anr-dimensional space. Thus, the arguments of eachr-dimensional point correspond to ther measured responses of each object in the finite population of objects. The null hypothesis underlying MRPP is that the observed sample of objects within groups of a specified size structure is randomly obtained from the pooled collection of objects comprising the finite population. The procedure is used to test the presumed geomorphic differences among three reaches of the Lower Mississippi River. A combination of the proposed reaches is favored and several variable-based reach configurations are proposed.