Dear Root team,

Using RooFit in ROOT 5.22, I would like to do an extended likelihood fit with MINOS to a set of data at a certain error level (yielding e.g. a 5 sigma upper and lower limit, instead of the standard 1 sigma), and given a signal + background model. How do I set the error level AND make the fit extended? At the moment, the part of my code relevant to the question looks like this:

[code] RooAddPdf *spb = new RooAddPdf(“spb”,“spb”,RooArgList(*sig,*bkg),RooArgList(*fsig,*fbkg));

RooNLLVar spb_nll(“spb_nll”,“spb_nll”,*spb,*data,Extended(kTRUE));

RooMinuit m(spb_nll);

double errorLevel = 5.*5.*0.5;

m.setErrorLevel(errorLevel);

m.fit(“eh2”);[/code]

Is this the correct way to go? The result looks reasonable, but I can not judge whether the fit was actually extended or not, especially since I also tried a composite likelihood fit (i.e. excluding fbkg and Extended(kTRUE)) to the same data and got exactly the same result.

Many thanks in advance!