Hi,
I am coming across a lot of cases where people are talking about, or using TTest when they are comparing campaign response rates, membership renewal rates, etc.
My understanding is that the TTest is not appropriate for such cases. And that people are confusing the TTest 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 ttest which are meant for continuous dependent values be used for comparing proportions/ratios?
Thanks
Tags: chi square, proc GLM, t test, test for difference in proportions

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