TH1::Scale -> error scaling

ROOT
1

Hello :slight_smile:

I have a question about how TH1::Scale scales histogram errors. Comment in
the source code says that the errors are scaled but does not say how.

In particular, if I have a histogram with big number of entries (i.e. with
a very good statistics and relatively small errors) and then scale this
histogram. Will my errors remain relatively small or the new histogram
will be treated as a one with little statistics and the relative errors
will increase?

Thanks a lot :slight_smile:

2

If you have the code, you should have the answer.
The sum of squares of weights for each bin is multiplied by the square of the scaling coefficient.

Rene