thoughts anyone?
thanks.
R
On Oct 31, 2005, at 6:10 PM, Robin Goldman wrote:
> Hi there,
>
> I'm not sure how to set up a comparison in a 3 level design. Subjects
> underwent ten 5 minute
> scans, and in each, they were presented novel stimuli. These novel
> stimuli were repeated 2 scans
> later, so the novel items (nov) in scan 1 were presented again
> (repeatNov) in scan 3 (along with
> more nov items), the ones in scan 2 were repeated in scan 4, etc.
>
> So, for 15 subjects, I have 10 scans each, and want to do a contrast
> looking at repeatNov-Nov, so
> repNov3 vs nov1, repNov4 vs nov2, repNov5 vs nov3, ...
>
> I assume I set this up in some way as a paired t-test in a second
> level for each subject, then
> combine these in a 3rd level....
>
> But things get trickier... I want to look not just at mean changes,
> but also at linear decreases
> across the scans and exponential decreases across the scans for this
> contrast. I know how to do
> this if the repeats were in the same scan and I could set up the
> contrast in the first level, but...
>
> um...
>
> Thanks!
> Robin
>
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