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Dear Rooters, I am new to the list, and I have the following which I coud not figure out how to do it under root. I'm fitting my J/psi peaks by a Gaussian function : f=N*Exp[-(x-\bar{x})^2/2 sigma^2]. Then I utilized the function Integral(min,max) to find the area or the number of counts under this fit. . . . n[j]->Fit("Gaus","R"); G->SetParameters(par[0],par[1],par[2]); float mean = par[1]; float sigma = par[2]; float mlo = mean-3.0*sigma; float mhi = mean+3.0*sigma; cout <<mean<<" and "<<sigma<<" and " <<mlo<<"and "<<mhi<<endl; float binw = n[j]->GetBinWidth(1); double COUNTS = G->Integral(mlo,mhi)/binw; . . . I need to know how to find the statistical error of the integral, i.e. "COUNTS" in root. Thank you very much Ahmed. ===== "EAST OR WEST, HOME IS BEST". Ahmed Al-Jamel Physics Department(http://www.physics.nmsu.edu) New Mexico State University Box 30001, MSC 3D Las Cruces, NM 88003-8001 Tel (off): (505)-646-7614. http://www.feynman.nmsu.edu http://www.phenix.bnl.gov/phenix/WWW/publish/ahmed1/ __________________________________ Do you Yahoo!? Get better spam protection with Yahoo! Mail. http://antispam.yahoo.com/tools

**Next message:**Ahmad: "[ROOT] statistical error of Intergation"**Previous message:**Rene Brun: "Re: [ROOT] Problem with tree4.C"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

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