Type i error rates for divisive clustering methods for grouping means in analysis of variance

Five univariate divisive clustering methods for grouping means in analysis of variance are considered.Unlike pairwise multiple comparison procedures, cluster analysis has the advantage of producing non-overlapping groups of the treatment means. Comparisonwise Type I error rates and average numbers of clusters per experiment are examined for a heterogeneous set of 20 true treatment means with 11 embedded homogenous sub-groups of one or more treatments. The results of a simulation study clearly show that observed comparisonwise error rate and number of clusters are determined to a far greater extent by the precision of the experiment (as determined by the magnitude of the standard deviation) than by either the stated significance level or the clustering method used.