Problem getting the Sumw2 on ratio from normalized plots

Hi

I am trying to get the ratio of two normalized plots

``````       pad1->cd();

Full->Scale(1/Full->Integral());
Fast->Scale(1/Fast->Integral());

Full->SetLineColor(kRed);
Fast->SetLineColor(kBlue);
Full->SetTitle("Comparison");
Full->Draw();
Fast->Draw("same");
///////now the ratio plot