Print

Print


Hi folks -

How would one go about computing a standardized beta weight (in the regression
sense) from a cope or pe?

If I am correct, the pe's are (unstandardized) regression weights (b's).
Therefore, I'd need to multiply by the standard deviation of the predictor
and divide by the standard deviation of the data.  But I am unsure which
files would correspond to this.

The varcope seems to be not just be the deviation of the predictor, as that
should be the same for all voxels.  It also isn't the standard deviation of
the data, as this would be the same for all predictors.  Is it a ratio of the
two?

If that is the case, then do I just divide the cope by the varcope to get a
standardized weight?

I'm not interested in getting percent signal change in this case ... it is a
continuously varying parameter (from 0 to 1), so I'd like to get a beta
weight (or even part correlation).

Ed

--
Ed Vessel
U. of Southern California               [log in to unmask]
Dept. of Neuroscience
HNB, 3641 Watt Way                      http://geon.usc.edu/~vessel
Los Angeles, CA 90089-2520
(213) 740-6102