Date: Wed, 21 May 2008 00:27:44 +0100
Reply-To: Angshu Bhowmik <email@example.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Angshu Bhowmik <firstname.lastname@example.org>
Subject: comparing groups before and after treatment
Content-Type: text/plain; charset="us-ascii"
I wonder if anyone could advise me (a clinical doctor with no statistical
training) about the correct way to test whether people have improved in 8
variables (e.g. how far they can walk, blood oxygen levels, spirometry, etc)
after an exercise program. I think they have, and the patients love it, but
I need to formally confirm it in order to keep the service running.
If I understand correctly, simply doing paired t-tests or Wilcoxon's tests
on each variable is not correct because multiple comparisons make it more
likely that something will show up. Is doing multiple t-tests and changing
the desired p value to 0.05 / 8 i.e. 0.00625 the only way to do this?
Many thanks for your kind help
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