Hello,
I am a student at the University of York and would be very grateful if you
could perhaps give me some advice with regards to the following fsl-
related issue.
I am planning to run higher-level analysis for 19 subjects using an ANOVA
2x2 repeated measures - I have 2 factors, each at two levels: Valence
(positive and negative) & Arousal (high and low). (I.e. each subject
listened to the same stimuli, which were grouped according to these
categories)I've had a look at the feat manual but can't quite understand
the illustrated example. Would my design matrix look this:
Group EV1 EV2 EV3 EV4
Input1 1 -1 -1 1 1
Input2 1 -1 -1 1 1
Input3 1 -1 1 -1 1
Input4 1 -1 1 -1 1
Input5 1 -1 -1 1 1
Input6 1 -1 -1 1 1
Input7 1 -1 1 -1 1
Input8 1 -1 1 -1 1
Input9 1 -1 -1 1 1
Input10 1 -1 -1 1 1
Input11 1 1 1 1 1
Input12 1 1 1 1 1
Input13 1 1 -1 -1 1
Input14 1 1 -1 -1 1
Input15 1 1 1 1 1
Input16 1 1 1 1 1
Input17 1 1 -1 -1 1
Input18 1 1 -1 -1 1
Input19 1 1 1 1 1
The way I understand it - EV1 models the effect of A, EV2 of B, EV3 the
interaction between both & EV4 the grand mean (?)
With three F-tests being performed:
A 1 0 0
B 0 1 0
AB 0 0 1
I am new to fsl (& neuroimaging in general) so please forgive the naivety
of the following question as well - would I have to use the 4 lower-level
copes for (i) positive-valence vs baseline (ii) negative-valence vs
baseline (iv) high-arousal vs baseline (v) low-arousal vs baseline? OR 2
lower-level copes for (i) negative > positive valence (ii) high arousal >
low arousal??
I would be extremely grateful for any sort of advice or help you could
provide on this issue.
Best wishes,
Anne
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