I would appreciate if someone could give me a idea on what I could possibly infer from a residual vs fitted plot for a non linear regression. If i have understood residuals correctly it would indicate whether or not my model predicts the data well. In the figure I have plotted the sinc fit to the data and the actual data vs the right ascension(or distance)and below that is the residual vs fit plot. The inferences I could make from this is:
- the sinc function does not predict my data well and I would probably need a more complex function like sinc² .
2.If I am assuming the system noise(0.027) to indicate standard deviation of the fit, would it make sense that I consider fit to be good if the residual variance of the amplitude lies within 2std.dev of the zero line.
Any other comments, corrections and explanations would really help. Thanks