It's not a matter of accuracy in this case, it's a matter of whether the regression has any meaning at all. Any regression can fit two data points, even a parab

It's not a matter of accuracy in this case, it's a matter of whether the regression has any meaning at all. Any regression can fit two data points, even a parabola. Of course, there are intuitive reasons to suspect that that is not the actual form of the distribution, but you can't actual show it from data with just two points. But I have to assume that you did more data points when you actually performed this study yourself. Up to that point the methodology is really useful, so don't take this as criticism of the entire post.