I’m training a BDT Classifier to reject background events of my data sample to increase the purity. I was reading the TMVA Users Guide and in section 3.1.13 it says:
Another useful aspect of the probability integral transformation (rarity) is the possibility to directly
visualise deviations of a test background (which could be physics data) from the training
sample, by exhibition of non-uniformity
So, I habilitate the “CreateMVAPds” flag and plotted Rarity to check. The result can be seen below.
What does it mean? And, how can I avoid it?
I’m passing as signal an MC sample with a cut in the signal region, and for background, I’m passing the wings of mass distribution far from the signal region.