i have a original histogram(hInvMassAll). I am fitting it with a gaussian. I want to get the number of entries under this gaussian. My original histogram has about 8000 Nentries…but the method
double ar=fit1->Integral(2.8,3.3);
gives value in the range of 200.
can anyone please tell me what is the correct way of doing it
with regards
arshad
bool Integrate()
{
TFile *f = TFile::Open(“MUONhistos.root”);
TH1F hist = (TH1F)(f->Get(“hInvMassAll”));
// hist->Fit(“mygaus”,"","",2.8,3.3);
TF1 f1(“f1”,“gaus”,2.8,3.3);
f1.SetParameters(1,-0.5,1);
hist->Fit(“gaus”,“w”,“M”,2.8,3.3);
TF1 fit1=(TF1)hist->GetFunction(“gaus”);
fit1->Draw();
double ar=fit1->Integral(2.8,3.3);
cout<<ar << endl;
// TF1 *f1= new TF1(“mygaus”,fitfunction,0,10,3);
TCanvas *c1 = new TCanvas(“c1”,“c1”);
hist->Draw();
return kTRUE;
}