On Fri, Aug 24, 2012 at 4:27 PM, s0675204 <[log in to unmask]> wrote:
> Dear SPM-ers,
>
> I was wondering if someone could help me understand this analysis.
>
> When doing a one sample t test with a co-variate (trait anxiety) at the
> second level: what is the difference between entering the contrast 0 1
> to look at the correlation between your co-variate and activity versus
> entering the contrast -1 1?
The contrast [0 1] tests whether there is a significant positive
relationship between your activity/connectivity and trait anxiety
measures.
>
> What specifically does the contrast -1 1
> demonstrate?
The contrast [1 -1] doesn't tell you anything. It tests whether the
mean activity is different than the slope of anxiety measures. This is
completely meaningless.
>
> Many thanks for any suggestions!
>
>
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