FindFit and NormFunction (to find a best fit by medians)

*To*: mathgroup at smc.vnet.net*Subject*: [mg91702] FindFit and NormFunction (to find a best fit by medians)*From*: Stern <nycstern at gmail.com>*Date*: Sat, 6 Sep 2008 02:05:30 -0400 (EDT)

I'm trying to use FindFit to find a best linear fit using Medians rather than Mean At one time, I believe the following code worked (I used it in several places, and never noted it failing, but it hasn't been used in a while and I don't actually remember): FindFit[sampledata,a+b*x,{a,b},x,NormFunction->(Sqrt[Median[#^2]]&)] Now, Mathematica seems to pass unevaluated expressions to the NormFunction, causing Median o fail with a "rectn: Rectangular array of real numbers is expected at position 1" error. I would appreciate any guidance. Michael