Curve fitting in Igor without minimizing chi square and minimizing some other terms

I know while doing a curve fitting we generally find the best fit which has least chi square.  can we change chi square to some other things to minimize in igor while curve fitting?

 

Thanks: Rabindra Dulal

You can request "robust fitting" in Igor. That does least absolute error instead of least squared error. To do other merit functions (you probably want maximum likelihood fitting?) you must write a merit function for it and use the Optimize operation to find the best value of the merit function.