Brablo science forum addict
Joined: 05 May 2005
Posts: 61

Posted: Sat Jun 24, 2006 4:36 am Post subject:
Math packages which fit curves



Is there a math program which can "guess" or figure out the functional
relationships between 2 or more variables using all kinds of
transformations?
For example, I was trying to correlate population density with the
1/population and 1/area. Of course, we all know the equation for
population density (population/area), but I just wanted to see what the
correlation would be when you have the *COMPONENTS* of the dependent
variable. The R^2 was 0.38.
The reason why I'm interested in this is because I'm convinced that
there are many relationships which are (1) exact (or more exact), and
also (2) much simpler than a linear approximation.
Suppose that you regress Y with X1 and X2. Is there a program which
regresses Y with:
1. x1 + x2 + x1*x2
2. x1^a * x2^b
3. x1^2 + x1 + x2^2 + x2 + x1*x2
4. Ln x1 + ln x2
5. ce^(a*x1) + de^(b*x2) + e
..
..
..
N. f(x1,x2)? 
