Simply put: Can I compare to third level analyses in a within subjects fashion.
There were two conditions in MRI session 1. Subjects performed a task (manipulation) and did not (rest).
I have the group effect for these contrasts corresponding to MRI 1.
Subjects then participated in an intervention.
There were two conditions in MRI session 2 (after the intervention). Subjects performed a task (manipulation) and did not (rest).
I have the group effect for these contrasts corresponding to MRI 2.
Am I being too liberal? Am I treating within subject variability as between subject variability? The analysis comes out beautifully. I also ran a paired-t test with the same data, and the images come out speckled. I've checked for outliers and have reran the analyses dozens of times to no avail.
Thanks.
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