Mean error calculation with negative entries

ROOT
1

Hello,

The mean error is calculated as being RMS/sqrt(no. of entries). My problem is that I need the mean error from a histogram which is obtained by subtraction from other histogram, and in some cases I have negative entries, and as a consequence the mean error is nan.

Is there a common accepted solution for this cases, or should I just disregard this histogram?

Thank you,
Angela.

p.s. I’m using root version 4.04/02.

2

I have protected this case in the development version.
In your version, you can do:

myhist->GetXaxis()->SetRange(1,nbins);
myhist->GetMeanError(1);

Rene