afni.nimh.nih.gov

The 1-sided F calculation you are interested in can be done in 3dcalc (or ccalc or 1deval) using the expression

qginv(fift_t2p(x,df1,df2))

For example

ccalc -eval 'qginv(fift_t2p(2,1,10))'

outputs the value 0.886516

bob cox