Hello folks!
I have a simple greenhorn problem with the normalization of a 1D
histogram:
I have a Tree T containing a variable fY, the distribution of which I want
to plot in a histogram, normalized per event.
So, first I create the histogram (30 bins from -2 to 2):
dndy1 = new TH1F("dndy","dN/dy of pi0",30,-2.0,2.0);
Then I use T.Draw to fill the histo and plot it with error-bars:
T.Draw("fY>>dndy","1/(5000*4/30)*(fId==111)","e1");
I have normalized my histogram so that the integral of the distribution
gives me the number of selected entries (particles) per event):
"1/(5000*4/30)" = 1/number_of_events_in_tree * 1/bin_width
However, the error-bars are not getting renormalized (i.e. rescaled)
properly (or at all) - the result is far too large error bars for the
distribution.
What am I doing wrong and how to I get the proper error-bars for my
normalized histogram?
Would it not be more convenient to at least have the division by the
bin-width automatically done in the histogramming, i.e. in the fill
method?
Thanks a lot for the help!
Steffen
PS: I have tried to fill out the registration form, but somehow your
computer does not respond when I click on the "submit registration"
button...
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Steffen A. Bass email: bass@nscl.msu.edu
Cyclotron Laboratory http://www.nscl.msu.edu/~bass
Michigan State University office: (517) 333-6434
East Lansing, MI 48823 FAX: (517) 353-5967
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