Hi Stefan,
I think a better analysis for your problem will be multilevel logistic regression.
You can take the binary outcome variable as dependent and the grouping variable as independent.
You can add other covariates in the model as well if required. Time variable should indicate the number of levels.
HTH
Muhammad
--- On Thu, 8/28/08, Stefan Uhmann <[log in to unmask]> wrote:
From: Stefan Uhmann <[log in to unmask]>
Subject: right test for the following design
To: [log in to unmask]
Date: Thursday, August 28, 2008, 7:45 PM
Hi,
I have got the following design:
3 groups of individuals and for each individual a binary outcome at two
points in time: pre and post. This gives my the following table:
G1 G2 G3
t1-yes 70% 40% 30%
t2-yes 80% 60% 20%
If I could use GLM, I would have an 3 x 2(group x pre/post)-GLM, with
the second factor being a within factor and the possibility to
differentiate between main and interaction effects.
Since my outcome is binary (yes-no) and I just want to use the
yes-portions as outcome, I have no idea which test to use. Is it
possible to use a chiČ-test, although one of the factors is a within factor?
Thanks for any help in advance,
Stefan
|