void f2()
{
	static Int_t nf = 10;
	auto can = new TCanvas("c1", "c1", 800,500);
	gStyle->SetOptStat(0);
	auto hh = new TH1F("hh", "Averaging functions", 100,0,10);
	can->Draw();
	hh->Draw();
	TF1 * fp[nf];
	TString fn;
	for (Int_t i=0; i<nf; i++){
		fn = "f"; fn += i;
		fp[i] = new TF1(fn, "[0]*x - [1]*x*x", 0, 10);
		fp[i]->SetParameters(60, 4 + gRandom->Gaus(1,0.3));
		fp[i]->SetLineColor(i+2);
		fp[i]->SetLineWidth(1);
		fp[i]->Draw("same");
	}
	Int_t npoints=20;
	Double_t x,y, dy = 10./npoints;
	auto avg = new TGraph(npoints);
	for (Int_t ip=0; ip < npoints; ip++) {
		x = dy*ip + 0.5*dy;
		avg->SetPoint(ip, x, 0.);
	}
	for (Int_t i=0; i<nf; i++){
	 	for (Int_t ip=0; ip < npoints; ip++) {
			avg->GetPoint(ip, x,y);
			avg->SetPoint(ip, x, y + fp[i]->Eval(x)/(Double_t)nf);
		}
	}
	avg->SetMarkerColor(1);
	avg->SetMarkerSize(1);
	avg->Draw("* same");
	hh->SetMaximum(300);
	can->Modified();
	can->Update();
}