void hist030_TRatioPlot_residual()
{
   gStyle->SetOptStat(0);
   auto c1 = new TCanvas("c1", "fit residual simple");
   auto h1 = new TH1D("h1", "h1", 50, -5, 5);
   h1->FillRandom("gaus", 2000);
   h1->Fit("gaus", "0");
   h1->GetXaxis()->SetTitle("x");
   auto rp1 = new TRatioPlot(h1);
   rp1->Draw();
   rp1->GetLowerRefYaxis()->SetTitle("ratio");
   rp1->GetUpperRefYaxis()->SetTitle("entries");
}