Hartung, JoachimMakambi, K. H.2004-12-062004-12-061999http://hdl.handle.net/2003/492510.17877/DE290R-5425The variance function of the optimal estimator of the overall mean in a heteroscedastic one-way ANOVA model is dominated by positive semi-definite quadratic functions. This makes it possible to develop closely related tests on the nullity of the overall mean parameter, in one-way fifixed and random effects ANOVA models, which make use of the quantiles of the t-distribution. These tests are founded on the convexity arguments similar to Hartung (1976). Simulation results indicate that the proposed tests attain type I error rates which are far more acceptable than those of the commonly used tests.enUniversitätsbibliothek Dortmundbalanced and unbalanced samplesestimated degrees of freedomfixed and random effects modelshomoscedastic and heteroscedastic error variancesreplicationtype I error rate310report