So, since I don't think this is possible directly, I want to use ccalc to convert from the desired p-value to the statistic threshold value. However, I can't make sense of the documentation for the specific function I want. I am working with "fico" data of correlation coefficients. It seems that what I need is:

ccalc -expr 'fico_p2t(p,a,b,c)'

However, I can't find any specific explanation of the latter 3 arguments. The documentation for the corresponding option in cdf lists the parameters as

SAMPLES FIT-PARAMETERS ORT-PARAMETERS

The first is clear, but I'm not sure what the others actually are. In particular, how do they relate to the inputs to 3dfim+ that I used to generate the fico file in the first place?

Using 3dinfo I got the statpar as 20 1 2. 20 makes sense, that's the number of samples, of course. But not sure what 1 and 2 represent.

Thanks...