RooMCStudy::plotPull - extracting gaussian fit parameters

Roofit and RooStats
1

Hello,
this in my first post so I hope I’m posting in the right section.

I’m using class RooMCStudy in order to simulate the reciprocal influences of various backgrounds in my invariant mass region. I would like to study pull distribution of fitting yields, and I would like to extract the parameters ( pullMean and pullSigma ) from the fitted Gaussian distribution of the pull, when I call:

But in the returned frame there are only a RooCurve, a RooHist and a TPaveText (and not a Roo*Pdf) so I don’t know to extract these parameters (as a Double_t for example).

Thank you for your help!
Best regards,
Davide

2

Hi,
Can you please post a simple running macro showing your problem ?

Thank you

Lorenzo

3

One simple workaround I have been using is to extract the plotted histogram, do a manual fit and extract the parameters. Here’s the example code in python (not tested):

4

Hi,

This should be fine or, you can do what is done inside RooMCStudy::plotPull (i.e. using RooFit).
See root.cern.ch/doc/master/RooMCSt … tml#l01334
Unfortunately, looking at the code the parameter values are not saved and returned to the user, they are just written in the text box.

Lorenzo

5

Ok, maybe the better solution is to do what is done inside RooMCStudy::plotPull, copying those lines.

Thank you again