Fit statistics

From: Woon-Seng Choong (wschoong@lbl.gov)
Date: Sat Feb 12 2000 - 01:19:12 MET


  I am using v2.23/10 on HPUX10.2 running aCC. I have a macro that plot
several points and do a linear fit. The error on the fitted parameters is
truncated in the stat box.  Is there a way to fix this?  Below is
the macro I used.

	Seng


void plot_mombias() {
  gROOT->Reset();
  c1 = new TCanvas("c1","HMC Output vs Beam Momentum",200,10,700,500);
  c1->SetGrid();
  
  // draw a frame to define the range
  TH1F *hr1 = c1->DrawFrame(140,-0.005.,190,0.03);
  hr1->SetXTitle("Average Beam Momentum");
  hr1->SetYTitle("HMC Estimate - Input Generation Value");
  hr1->SetTitleOffset(1.3, "Y");
  hr1->SetTitle("HMC Output (Input g=-0.2154) vs Average Beam Momentum");
  
  const Int_t n = 8;
  Float_t x[n]  = {147.577700,152.554231,157.480476,162.457551,167.479134,172.467954,
                   177.447382,182.435490};
  Float_t ex[n] = {0, 0, 0, 0, 0, 0, 0, 0};
  Float_t y[n]  = {.12963e-1,.11759e-1,.06063e-1,.08780e-1,.10120e-1,.10231e-1,
                   .12242e-1,.10814e-1};
  Float_t ey[n] = {2.82768e-03, 2.43126e-03,2.17597e-03,2.02725e-03,1.97245e-03,1.94164e-03,
                   1.97880e-03, 2.05305e-03};

  Float_t chi2[n]  = {344.125, 368.906, 390.534, 304.297, 383.312, 359.423,
                      417.878, 393.309};
  Float_t dof[n] = {285, 285, 284, 288, 287, 291, 289, 292};


  // create graph
  gr = new TGraphErrors(n,x,y,ex,ey);
  gr->SetMarkerColor(kBlack);
  gr->SetLineColor(kBlack);
  gr->SetMarkerStyle(20);
  gr->Draw("P");


  gStyle->SetOptFit(111);
  gStyle->SetStatW(0.2);
  gStyle->SetStatH(0.1);
  TF1 *f1 = new TF1("f1", "[0]+[1]*(x-155)", 145, 185);
  gr->Fit("f1");

  c1->Print("hybrid_mombias.eps"); 


}



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