Some Multiple Range Tests for Variances

Often times, the experimenter is interested in making inferences about treatment variances instead of, or in addition to, inferences about means. Three multiple range tests are proposed for the purpose of specifying which treatment variances or sets of variances are homogeneous. The procedures are based upon the F max statistic, Cochran's statistic, and a normalizing log transformation of the sample variances. All three tests depend heavily upon the underlying assumption of normality.