I am having trouble deciding what type of analysis to use for the following data:
I have two groups (one control, one treatment) and took a pre-measure of my dependent variable, and then 3 post-measures.
I am interested in understanding if the treatment affected the dependent variable over the course of the study.
I originally did a rmANOVA, and found no significant interaction (treatmentxtime), but found a main effect of the treatment. I think this means that the treatment group was different than the control over the entire study, including before treatment began.
My question is, is there a better analysis that takes into account if the groups were in fact different before treatment? With a t-test, they were not different, but somehow with all of the data throughout the experiment, they are different.