An Extension of the T-Method of Multiple Comparison to Include the Cases with Unequal Sample Sizes

Abstract Under fairly general conditions the studentized range can be used to approximately simultaneously estimate all linear combinations of a set of means for an unbalanced AOV fixed effects model. These new methods are called extended Tukey procedures (Ext-T). Comparisons are made with the Scheffé (S) procedures. It is recommended generally that the (Ext-T) procedures be used if primary interest is in pairwise comparisons of the means and if the unbalance is not severe.