Hi, I don’t know I can ask here my question.
I have tried to normalization with two method.

with DrawNormalized
h->DrawNormalize(“histo”);

with Scale 1 and Draw.
Double_t Norm=h->GenEntries();
h->Scale(1/Norm);
h->Draw(“histo”);

My friend said that "DrawNormalized " also gives the plot which entries are normalized by 1. However I have obtained quite difference results for two cases.
I have attached my histograms to help your understanding

original histogram

Draw Normalized

Scaled by 1 then Draw
4.second and third histogram draw “same”

I think that the “Scale” method doesn’t handle the weights properly. I have just found a difference when trying to normalise weighted histograms. If you plot the integral after scaling you will figure out that the weighted one gives a result equal to the average weight value while the non-weighted one gives you integral=1 .