[a,b,thresh50] = FitLogistic(inputs,nYes,nNo)
Fit a logistic function to YN psychometric data.
Returns logistic parameters and 50% threshold.
The form of the logistic equation is pYes = 1/(1+10^-(a*inputs+b))
The logistic is not a good function to use for serious work,
but you can do a quick and dirty fit analytically and
you can explain it to students more easily than some
other candidate models for psychometric functions.
2/8/97 dhb Wrote it.