It has been a while since I have done some stats, and I have tried to fit a curve using optimize.curve_fit of parameter estimation. I am also interested in the standard deviation of the fitted parameters which I get from the square of the diagonal terms of the covariance matrix. In order to get the estandar deviation I need that the number of data being greater than the number of parameter to fit.
My question is following: Why should be the number of data greater (>) than the number of parameters to fit, and not greater or equal (>=)?
Probably is something quite simple, sorry. I suspect that it might have something to do with the degrees of freedom minus one, but not really sure why.
Best regards Dani