Get expectation value of parameter from model


I’m hoping this is a really simple Roofit question… I have a model (pdf) constructed from lots of parameters and functions of parameters and forming products of pdfs based on these functions and parameters. Is there a quick way to extract the expected value of a set of parameters that represent the observables in my model?

E.g. if I had a model like this:


I have a RooArgSet representing the observables, which I choose to be (n,p,q). Can I quickly ask the pdf to give me their expected values, which in this case would be (s+b, s, b) ? And by this I mean simply the values of s+b, s and b, I don’t need to have the functions/parameters actually returned (although obviously I could get the values by doing getVal() with each, if that was what was available).