<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />Hello,
When I perform a quadratic regression, it returns the form y=a+bx+c(x-d)^2. I would like it in the form y=a+bx+cx^2 so that I can have the correct parameter estimates. How can I do this - either change the way the model returns or change the parameters as needed?
Thanks,
Brian
Thanks Kevin! Exactly what I was looking for!
Hi, Brian!
Try using the Fit Special... dialog of the Fit Y by X platform (Under the LIRT by Bivariate Fit).
Leave both Y and X as No Transformation, specify the degree as 2 Quadratic, and uncheck the Centered Polynomial checkbox. That will give you the model you seek.
As an aside, JMP almost always centers the variables in analyses since it makes a lot of statistical sense (makes parameters comparable, etc.).
As another, more distant, aside LIRT stands for Little Inverted Red Triangle.
