My dataset consists of many patients who went through a treatment and I want to understand if there is a difference between before and after taking it. By far it appears clearly as a Paired Samples t-test, the problem is that I have different historical observations on each patient and let's say I have:
- patient A with 150 observations before and 350 observations after,
- patient B with 50 observations before and 300 observations after...
Which test should I use? The one for paired samples (even though n_before ≠ n_after)? A most general Welch's t-test (they are heteroschedastic)?
Is there anything I am missing or doing wrong?
In case of paired samples should I need to use undersampling in order to make the lenghts match?
Thanks to everyone
