How does root treat zero error bins when fitting

ROOT
1

Hello All,

When fitting a TProfile, what does root do with bins that have zero errors (due to single entries into these bins)?

Thanks,
Raz

2

By default these bins are ignored. However if you call teh static function
TProfile::Approximate();
then the bins with only one entry will have their errors computed by looking at the neighbour bins.

Rene

3

Thank you!

Raz

4

BTW, maybe it’s better to rephrase this text in the TProfile page, I think it’s misleading:

In the special case where s(J) is zero (eg, case of 1 entry only in one bin)
e(J) is computed from the average of the s(J) for all bins.
This simple/crude approximation was suggested in order to keep the bin
during a fit operation.

Thanks,
Raz

5

Thanks for this comment. I have updated the documentation of TProfile accordingly.

Rene