Are joint tests of model coefficients possible in limma? I'm not asking about contrasts, but if we can test if two or more model coefficients are different from zero. An example might be if you wanted to test group AND group*time coefficients in a model with group, time, and group*time terms, to understand the total effect of group, which requires a joint test of all terms in which group is included. This can be done via an F-test (or LRT) of full (group, time, group*time) and reduced models (time), typically. In reading the limma manual, I've missed this useful test. Can it be done inside the limma commands. Is there an example someone can point to?