EXACT AND APPROXIMATE DISTRIBUTIONS FOR LINEAR CONTRASTS OF MEANS AND VARIANCES

A Bayesian analysis is presented for the K-group Behrens-Fisher problem. Both exact posterior distributions and approximations were developed for both a general linear contrast of the K means and the K variances,- given either proper diffuse or informative conjugate priors. The contrast of variances is a unique feature of the heterogeneous variance model that enables investigators to test specific effects of experimental manipulations on variance. Finally, important differences were observed between the heterogeneous variance model and the homogeneous model. © 1979, Taylor & Francis Group, LLC. All rights reserved.