THE ML ESTIMATOR OF DISPERSION EFFECTS IN UNREPLICATED FACTORIAL EXPERIMENTS

Abstract

In unreplicated factorial experiments,if the dispersion effects of factors A,B are active,the existing estimators of dispersion effects are often biased whether or not the dispersion effect of interaction factor AB is active.This results in AB be spuriously identified active factor.In this paper,we propose a new estimator of dispersion effects(called the ML estimator),and give the exact expression of the variance of ML estimator.We prove that the ML estimator of dispersion effect of interaction factor AB is unbiased in a class of models. Finally,a comparison is given between the ML estimator and the existing and commonly used estimators.