int testPlotRes()
{
  RooRealVar x("x","x",0.,-5.,5.);
  RooRealVar m("m","m",0.,-3.,3.);
  RooRealVar s("s","s",1.,0.5,1.5);
  RooGaussian g("g","g",x,m,s);
  
  RooDataSet *data = g.generate(x,10000);

  RooPlot *frame = x.frame();
  data->plotOn(frame);
  g.plotOn(frame);

  frame->GetXaxis()->SetTitle("");
  frame->GetXaxis()->SetLabelSize(0);
  frame->GetYaxis()->SetLabelSize(0.05);

  RooPlot *residual= x.frame();
  RooHist *resHist = (RooHist*)frame->pullHist();
  residual->addObject(resHist,"PZ");
  residual->SetMinimum(-5.);
  residual->SetMaximum(+5.);
  residual->GetXaxis()->SetLabelSize(0.1);
  residual->GetXaxis()->SetTitleOffset(0.8);
  residual->GetXaxis()->SetTitleSize(0.15);
  residual->GetYaxis()->SetLabelSize(0);
  residual->GetYaxis()->SetNdivisions(110);
 
  TCanvas *c = new TCanvas("c","c",400,400);
  c->Divide(2);
  c->GetPad(1)->SetPad(0.,0.3,1.,1.);
  c->GetPad(2)->SetPad(0.,0.,1.,0.3);
  c->GetPad(1)->SetBottomMargin(0);
  c->GetPad(2)->SetTopMargin(0);
  c->GetPad(2)->SetBottomMargin(0.25);
  c->GetPad(2)->SetFillColor(4000);
  c->cd(1);
  frame->Draw();
  TArrow* arrow = new TArrow(-6.5,30.,-5.5,10.,0.01,">");
  arrow->Draw();
  c->cd(2);
  residual->Draw();

  c->Print("test.gif");
  
  return 0;
}