TESTING SEQUENTIAL ASSOCIATION - ESTIMATING EXACT P-VALUES USING SAMPLED PERMUTATIONS

Assigning p values to all transitions in a matrix based on their z sco res is problematic on 2 counts: The z scores may not be normally distr ibuted,and transitions are interconnected. Permutation tests, which re quire fewer assumptions, are an attractive alternative to the standard asymptotic methods for assigning significance, Moreover, when asympto tic z scores are only somewhat above their critical value and sequence s are short, often the exact probabilities of permutation tests are no t less than .05. Log-linear and permutation methods may be used to win now the set of transitions initially identified as significant even fu rther. A computer program that program the performs these tests is ava ilable from the authors.