I'm using the numpy release, in particular polyfit (np.polyfit) to find a polynomial curve of degree 1,2,3, ... etc to adjust a set of points (x,y) , I get the coefficients of such polynomials, however , I would like to see if there is any way to get a measure of the adjustment error, which I can not find. It would be helpful if they helped me. I can only get the correlation matrix of X e Y .