Estimability,testability, and connectedness in the cell means model

This article discusses the conocepts of estimation of parameters and tests of linear hyp hypotheses in the fixed effects (ANOVA) model with some zero cell frequencies. The concept of connected experiments is generalized ot he cel1-means model and relatedtotheest imation of and test of hy pothe sesa bout the cell means. A simple test for connectedness is developed as a n atur alre sult of thea nalysis of the constrai nedcell means model. The a nalysis of unconnected experimentsisbriefly discussed. Examples are presented toillustrate the ideas.