Hartung, Joachim2004-12-062004-12-061998http://hdl.handle.net/2003/488510.17877/DE290R-6916In many fields of applications, test statistics are obtained by combining estimates from several experiments, studies or centres of a multi-centre trial. The commonly used test procedure to judge the evidence of a common overall effect can result in a considerable overestimation of the significance level, leading to a high rate of too liberal decisions. An alternative test statistic is presented and a better approximating test distribution is derived. Explicitely discussed are the methods in the unbalanced heteroscedastic 1-way random ANOVA model and for the probability difference method, including interaction treatment by centres. Numerical results are presented by simulation studies.enUniversitätsbibliothek Dortmundcombining experimentsheteroscedastic ANOVA modelinteraction treatment by centresmeta-analysismulti-centre studyprobability difference methodrandom effects310report