Parameter Error returned by minuit

It might be a stupid question but I really need to make things clear…

Can someone explain me what are the error values returned by a fitting procedure…

The reason is: I’ve fitted a set of data with root and another program. Both of them returned me quite the same value for the parameter I was looking for.
But the errors are completly different. If ones look nice I have to undestand why is the difference so big.

Thanks a lot !

PS: Unfortunately the Minuit package description don’t fully answer my question

see the following document about error interpretation in Minuit: … nerror.pdf


Thank you

I had not found that document. It’s time to read!