# TProfile & RMS

Hi,
reading the doc for TProfile: “Profile histograms are used to display the mean value of Y and its RMS for each bin in X” I assume that the RMS for a projection of the i-th bin is equal to what’s displayed as the “error” line in a TProfile. It seems that’s wrong, attached plots and an example macro show that: the center is where it’s supposed to be (0.8606), but for the 5th-bin projection the RMS is 0.1727, whereas the TProfile shows 0.00085. This looks like the error on the mean, but I’d like to see the RMS there. How can I make TProfile to have line lengths equivalent to the RMS? I couldn’t find anything in the docs.

linux, cvs root 4.03/01 2 February 2005.
Axel.
profile_rms.C (430 Bytes)

Axel,

You should use the option “S” in the constructor. See:
root.cern.ch/root/htmldoc/TProfile.html
root.cern.ch/root/htmldoc/TProfi … e:TProfile
root.cern.ch/root/htmldoc/TProfi … ildOptions

Rene

Great, thanks Rene! I didn’t realize from the doc that “s” is what I was looking for…
Axel.