IntegralError give impossible result

[Wile_E_Coyote]

Compute uncertainty of integral of a component of a TF1

Hi, I am wondering whether there is functionality in standard ROOT (not RooFit) to compute the uncertainty of a component of a TF1. E.g. if fitting a function TF1 f1(“f1”,“gaus(0)+pol2(3)”) to a spectrum, I’d like to get the integral and its uncertainty only for the gaus(0) component. If there is no function available, how can I properly can do this myself? Another related question: If using a signal component, where the “amplitude” parameter already represents the integral (like it should b…