Hi,

There are probably multiple ways to do this, but here's what I recommend for your first design (I believe yours is rank deficient)

EV1:  1 for G1 Cond1, -1 for G1 Cond2, 0 for all G2
EV2:  1 for G2 Cond1, -1 for G2 Cond2, 0 for all G1
next 20 EV's are the subject-specific means (your S1-S20)

Then the contrast [1 -1 0....0] tests the group differences in the paired differences (i.e. your interaction effect).

For the second design, I'm extrapolating from what was proposed in this FSL list email, which apparently was summarizing from an earlier email you would have:

EV1:  1 for G1 Cond1, -1 for G1 Cond2, 0 for all G2
EV2:  1 for G2 Cond1, -1 for G2 Cond2, 0 for all G1
EV3:  avg estrogen for this subject in G1 Cond1, -1*avg estrogen for this subject G1 Cond2, 0 for G2
EV4:  avg estrogen for this subject in G2 Cond1, -1*avg estrogen for this subject G2 Cond2, 0 for G2
EV's 5&6, similar to 3&4, but for progesterone
next 20 EV's are the subject-specific means (your S1-S20)

This will control for whether the within-subject difference is a function of estrogen or progesterone levels.  

Hope that helps!

Jeanette


On Tue, Jul 24, 2012 at 2:22 PM, Klara Mareckova <[log in to unmask]> wrote:
Hi,

I have a question about repeated measures anova and covariates design.
I was reading the FSL manual and forum but since none of the examples
seem to fit my situation, I was wondering whether some of you
experienced FSLers could confirm whether I got it right/ what do I
need to change.

Design # 1: Repeated measures anova - 2 groups (medication, control),
each participants scanned twice =  two different conditions (cond1,
cond2). I want to have a look at the main effect of group, condition,
and the group by condition interaction. I have 40 subjects all
together; 10 in group1 cond1, 10 in group1 cond2, 10 in group2 cond1,
10 in group2 cond2. I'm combining the F test with the repeated measure
design - can you please check list 1 of the attached spreadsheet and
see whether the design # 1 is correct?

Design # 2: Repeated measures anova with 2 continuous variables. The
same dataset as above, but this time I want to look at the effect of
two hormone levels - estrogen and progesterone and just correct for
the fact that each participant was scanned twice (I believe that the
group and condition are described by the two hormone levels). I'm
combining the covariate analysis with the repeated measure design -
can you please check list 2 of the attached spreadsheet and see
whether design # 2 is correct?


Thanks a lot for your feedback and advice,

Klara