Fitting using Chi2

Dear all,
if we introduce a user function for fitting a point data. then we just perform
where “eff_function” is the fitting function.
is the default fitting method in ROOT is the chi2 method??


Thank you for replying.
I have “TGraphErrors” but the errors are in the Y values rather than X-values.
TGraphErrors *gr1 = new TGraphErrors(“eff2.dat”, “%lg %lg %lg”);

In the manual it says the default fitting function is Chi2-method unless we have an error values for the X, it will be the “effectiveChi2” method

so does this mean if we have X values without error it will keep the Chi2 method?

There’s not much more to say. Without x errors, the “effective” method will not be used, so you get the default.

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