Hi Fatima,
In the second case you are using sub-brick 3 for thresholding
(masking) and sub-brick 2 for data values. In the first case
you merely input sub-brick 3 for both.
So in the first case the maximum intensity coordinates will
be different, because they come from the threshold values, not
the data values.
In the second case, since the intensities come from the data,
therefore they could be very small. The betas could be very
near 0 even though the t-stats exceed 8.23 (in abs()). So the
mean is not surprisingly close to zero.
You could create a mask with the thresholded and clustered data
and apply that via -mask to the data from sub-brick 2 in the
program 3dhistog, giving you a histogram of data values where
the statistic survives.
- rick
