[ROOT] Problem likelihood fit histogram with empty bin

From: Datao Gong (dtgong@physics.umn.edu)
Date: Wed Feb 26 2003 - 17:40:29 MET

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Hi,Rooters,
I fit my ntuple with likelihood method. I found if i tightly cut,
the fit result is much different and fit quality worse (ch2/ndf far
away from 1). Compare to min_fit, i found it is from the empty bins
in histogram. Likelihood method seems do not take into account
empty bin default. (I read Burn's email in roottalk02). In my case,
I fit my histogram with option "EMVL0", the ch2/ndf is 237/189, meanwhile,
mn_fit give me 190/191. I know there are two empty bins in my histogram.
If i set "W" option, the chi2/ndf is up to 3067/191. Is there something
wrong?

Gong Datao

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