> the results of this test could be biologically meaningful based on previous
> descriptions in the literature. I also want to see if the differences in the
> variance are brain-region specific.

To clarify, you just want to see whether the two groups have the same variability, without the involvement of those three explanatory variables (all within-subject factors?), right?

If so, one possibility is that, if you also have the t-statistic for each effect estimate (intensity), you could use 3dMEMA with option -unequal_variance, and obtain the ratio of the variances between the groups (that would be automatically output from the program). There is no statistic for the ratio that could provide significance testing, but it would give you some sense about the variability difference.

Gang



Edited 1 time(s). Last edit at 05/13/2013 05:06PM by Gang.