Dear ROOTors,
According to my study, I need to get the error of the mean value of a weighted histogram.
I have checked the code for calculating this error:
(from the root web)*// mean error = RMS / sqrt( Neff )*
The Neff is: (sum of Wt)^2 / sum of Wt^2
*// s[1] sum of squares of weights, s[0] sum of weights
return (s[1] ? s[0]*s[0]/s[1] :TMath <http://root.cern.ch/root/html/TMath.html>::Abs <http://root.cern.ch/root/html/TMath.html#TMath:Abs>(s[0]) );
*
Since I am not an expert on statistics, may I ask how this definition come? Where can I find some reference for this formula?
Thank you in advance
Best regards
Lei Received on Thu Feb 23 2012 - 09:11:39 CET
This archive was generated by hypermail 2.2.0 : Thu Feb 23 2012 - 11:50:01 CET