Dear all,
I'm sure this has been addressed before but my list search didn't run
up a clear answer (a reflection on my poor search skills than the
clarity of past answers, I am sure).
I am running a repeated measures type ANOVA design, with a group
(between subject) by time/session (pre-post, within subject) design.
After some consideration, flexible factorial seemed the best way to go.
I set for main effects of time and session, as well as the
interaction. My design matrix is attached.
I set independence for no for 'time', but not for group, while I left
variance unequal (after all we expect changes over time, so I expect
possible unequal variance).
First I wanted to check if this seems OK.
Second, I wanted to check if maybe we should model subject as an
additional factor? It seems to maybe be already embedded implicitly in
the flexible factorial. If I add this factor, but don't specify a main
effect, it doesn't appear in the design matrix, which I found a bit
surprising (it should still be modeled even if we don't contrast it,
for the effects on the Beta estimation).
Thanks a lot,
Colin
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