Thanks for your replies.

I was thinking nonlinear because the hypothesized behaviour for my data would be something that looks like a negative exponential function y=a-b*c^x (or a rational function) that approaches a horizontal asymptote after increasing initially. The premise of the study is hard to explain in a few words, but basically I'm expecting to see some kind of diminishing return after a certain level in X (independent var). It might be a matter of transforming the data first and then looking for a linear regression fit. I am not sure which. Does the choice of linear vs. nonlinear regression affect the data points needed?

Dason, I was also pondering whether or not I should average the data. After what you said here I am leaning on the side of not averaging the data. Would this solve my problem of too few data points for modeling purpose?

Thanks for your help!