I am coming across a lot of cases where people are talking about, or using T-Test when they are comparing campaign response rates, membership renewal rates, etc.
My understanding is that the T-Test is not appropriate for such cases. And that people are confusing the T-Test with the Two Sample test for proportions (which uses the Z stat). Personally speaking, I think the Chi Square test and its related tests (Fisher's Exact, Mc Nemar) are more appropriate for testing the differences in proportions/ratios.
There is one case where people have actually used a Proc GLM to test the difference in renewals among customer groups based on different communication channels. So how can proc glm or the t-test which are meant for continuous dependent values be used for comparing proportions/ratios?