P.Mean: Comparing pre and post data with a parallel control group (created 2008-09-25).

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I am retrospectively comparing pre and post treatment heart rates for two different populations. I was going to use a paired t-test for comparison within each population. Can I still use an independent t-test for comparison of the post treatment differences between the two populations? If not, what would be the most appropriate test?

Congratulations! Your approach is exactly what I would have suggested. For the record, there is a simple repeated measures design that would work here with group, subjects nested within group, time, and a time by group interaction. I'll try to write up the details on my website. But the test of interaction in the repeated measures design is equivalent to an independent sample t-test on the change score.

This work is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2010-04-01. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Mixed models.