Analysis of Multidimensional Contingency Tables by Exact Conditional Tests: Techniques and Strategies

摘要: The tests for zero partial association in a multidimensional contingency table (suggested by Birch (1965) and later used Wermuth (1976) more elaborate model- searching strategy) have gained new importance with the introduction of class graphical models. It is shown how these may be performed as exact conditional using test criteria either ordinary likelihood ratio, standard x2 statistic or any other appropriate (e.g. incorporating ordinal properties some categorical variables). A strategy model check- ing based exclusively on association, initially full subsequently marginal tables, presented. An example application given, which illustrates that usual approximate p-values are completely unreliable large sparse tables.