I have a question concerning the numbering convention of bins in histograms. Here a little extract from the root manual, v5.08, page 26:
Bin Numbering Convention
For all histogram types: nbins, xlow, xup
Bin# 0 contains the underflow.
Bin# 1 contains the first bin with low-edge (xlow INCLUDED).
The second to last bin (bin# nbins) contains the upper-edge (xup EXCLUDED).
The Last bin (bin# nbins+1) contains the overflow.
The last two lines describe both a “last bin”. Which is the last bin now? And do I have to set up “nbins+2” bins in my histogram creator in reality if I want to have “nbins” bins with data, cause of the under- and over flow (which would give me another two bins)? The convention is a little bit confusing, at least for me. Could some one maybe bring a little bit light in here?