#include "TFile.h"
#include "TH1.h"
#include "TH1D.h"
#include "TH2.h"
#include "TF1.h"
#include "TProfile.h"
#include "TString.h"
#include "TMath.h"
#include "TGraph.h"
#include "TCanvas.h"


void Projection(){
//
/
//

 
  TFile * b = TFile::Open("test.root");


TH1 *MetvsJetsTtbar  = (TH1*)b->Get ("NJETSvsMETTtbar");

TCanvas *proj = new TCanvas("proj", "Ttbar MET", 600, 600);

proj->cd();
MetvsJetsTtbar->Draw();

TH1D* px = MetvsJetsTtbar->ProjectionY("px", 160, 180); // where firstYbin = 160 and lastYbin = 180

px->Draw();

proj->Update();

}