I am trying to do an extended maximum likelihood fit in Roofit. I am not able to make sense of my results. I am fitting a dataset with some pdf that shouldn’t be able to fit it. peaking distribution (dataset) and 2nd order Chebyshev polynomial is pdf used. I don’t expect the fit to converge and also expect the yield returned from fitter to be completely different from the observed number of events (in this case size of the dataset). But this is what I get:
1> the fit is very bad as expected but MIGRAD did converge. Why ?
2> the yield returned from extended maximum likelihood fitter is exactly equal to the number of events read from dataset. How??