I have a problem about how to get the integral error of the TF1 function not from fitting?
The case is like I have a histogram contain both signal and background distribution. And I have a TF1 function consisting of signal part (Gaussian) and background part (3rd order polynomial). Now I fit the histogram with the function. I would like to integral the signal part to get the signal yield. The way I choose to get the yield is to set the parameters of the background to be zeroes and then to integral the function. But how could I get the integral error in this condition that I do not know what the covariance matrix exaclyt is.
Many thanks in advance.