is there any way to superimpose different RooPlots? I have a function which fits a distribution and I want to call it four times (on four different datasets) and plot everything (4 data histos plus 4 fits) over the same frame.
A RooPlot can contain any number of curves and histograms. A pdf projection will always normalize
to the last added dataset, so fill a rooplot with 4 datasets and curves you would do the following
pdf1->plotOn(frame) ; // normalized to data1
pdf2->plotOn(frame) ; // normalized to data2