Say i have a set of points that aren't necessarily linear, but are planar, and all follow a 'general' trend in the same direction. Say, something like this: http://img343.imageshack.us/img343/2218/pointdistribution1jo.jpg [Broken] This is an entirely random example, but hopefully it'll help you get the picture. What i need to know, is how to create a polynomial function that curves, generally following these points. I'm researching regression, but from what i can see, i have to know what form the polynomial will be in, then solve for the coefficients. I need to know how it could be done, not knowing the form of the polynomial.