Dear SPM'ers
We have an activation study with three conditions (neutral (no emotion),
emotion 1, emotion 2) and four replications of each condition. Totally
there are 12 scans per subject. We have also two different groups of
subjects (10 and 11 subjects). The sequence of emotions is the same
across all subjects. The total amount of scans is 252.
The hypotheses are following:
1) To test the differences between conditions within both groups
separately (neutral vs emotion 1, neutral vs emotion 2)
2) To test the interaction between group and differences between
conditions (previous contrasts)
We analysed the data using The Full Monty and treated each replication
as a separate condition. However, we are not sure whether this is the
right way to draw population inferences.
Do we need a random effects analysis for testing our hypotheses?
If the random effects analysis is appropriate, how to implement it ?
There is some text about random effects analysis in spm_RandFX.man, but
we can't really figure out how to implement it in this kind of design.
Thank you,
Esa Wallius
Turku PET centre, Finland
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