Question

how can I tell If an exponential regresion model is better or if a quadratic regression model is better?

Answer 1

What are you looking at, a curve or a few points?

Answer 2

If the curve has a maximum or minimum, then a quadratic function is better.

Answer 3

If \(f(x_1+1)/f(x_1) \approx f(x_2+1)/f(x_2)\) then exponential function is good.