I need to conduct some non-linear regression analysis on some data I have.
I have all the data points and a curve that fits but I want to find the accuracy of the curve, hence I need to conduct non-linear regression analysis.
I have absolutely no idea how to do this. Is there something similar to r^2 for non-linear regression? I've done some research but it seems too complicated.
If there is a way to do this within excel that would be better but any help is appreciated.