[ROOT] Errors

From: Ilia Ravinovich (ravini@wicc.weizmann.ac.il)
Date: Wed Aug 15 2001 - 13:15:15 MEST


Hi Rene,

In my macro I'm doing:

inv_reb_signal_n->Add(inv_reb_real_n,inv_reb_mixed_norm_n,1.,-1.);
inv_reb_signal_n->Print("all");

I checked the output for example bin #10:

fSumw[10]=373.426, x=1.145, error=43.7226

But the error is wrong because:

fSumw[10]=1911, x=1.145 (this is from 'inv_reb_real_n')
fSumw[10]=1537.57, x=1.145 (this is from 'inv_reb_mixed_norm')

1911-1537.57=373.43, error=sqrt(1911+1537.57)=58.72

Am I doing something wrong?

Thanks,

Ilia

************************************************************************
*                                                                      *
*   Ilia Ravinovich                                                    *
*   Department of Particle Physics             PPE Division            *
*   Weizmann Institute of Science              Bld 892, 1D-015         *
*   Rehovot 76100                              CERN, 1211 Geneva       *
*   ISRAEL                                     Switzerland             *
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*   E-mail: Ilia.Ravinovich@weizmann.ac.il     Ilia.Ravinovich@cern.ch *
*                                                                      *
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