For the two-way layout with one observation per cell, consider the model whereby yij ∼ N(????ij, ????2) with

????ij = ????0 + ????i + ????j + ????????i????j

.

For independent observations, is this a GLM? Why or why not? (Tukey (1949)

proposed a test of H0: ???? = 0 as a way of testing for interaction; in this setting, after we form the usual interaction SS, the residual SS is 0, so the ordinary test that applies with multiple observations degenerates.)