Linear fitter problems in ROOT v5-28-00-patches

[moneta]

Thanks for the file, see the answer for the first question posted in

Minuit versus Linear fitter in ROOT v5-30-00-patches

While trying to fit a TGraph with a “pol3”, the “Minuit” gives me always worse “chi2” (in both cases below the “Fit Panel” interface was used). Is there any parameter I can change in order to “improve” it? [code]Minimizer is Minuit / MigradImproved Chi2 = 2216.32 NDf = 464 Edm = 7.8433e-11 NCalls = 77 p0 = 23210.3 +/- 1.36739 p1 …