Using TH1::IntegralAndError()

[Wile_E_Coyote]

Error on a integral

Well, you will need to check how you fill your histogram as Impact_mu_A->Print("all"); shows big bin errors: TH1.Print Name = Impact_mu_A, Entries= 4, Total sum= 2867.37 fSumw[0]=0, x=-0.5, error=0 # the underflow bin fSumw[1]=645.963, x=0.5, error=645.963 fSumw[2]=2221.41, x=1.5, error=1286.41 fSumw[3]=0, x=2.5, error=0 (...) fSumw[100]=0, x=99.5, error=0 fSumw[101]=0, x=100.5, error=0 # the overflow bin BTW. You probably want (excluding underflow and overflow bins): Double_t error_A;…

Use of IntegralAndError method!

Double_t error; Double_t integral = Hist->IntegralAndError(10, 70, error, ""); // "" ... or ... "width" std::cout << "Hist integral = " << interal << " +- " << error << std::endl;