Dear rooters,

I have a question that I’ve found a few times before but none of them help me solve this issue.

I am computing the chi2 value between two histograms changing two parameters and I would like to found the values of the parameters that minimize the chi2, and also the 1-sigma uncertainties of these parameters.

I have a two-dimensional histogram, with the first parameter in the x-axis and the second one in the y-axis, and this histogram is filled with chi2 values. In the figure there’s an example of how the histogram looks like, and in the `.root`

file I leave it attached.

chiplot.root (150.4 KB)

With respect to the values that minimize the chi2 I have no problem: I can just simply look for the minimum bin in the x and y direction. But, how can I get the statistical uncertainties of the parameters?

Thank you very much for your time

Best regards,

Francisco

*ROOT Version:* 6.22/01

*Platform:* macOS Catalina and lxplus