perform a quadratic model

#1
hi all.

I would like to develop a quadratic model (the highest n=2) with 3 independent variables (a,b,c).

I was running linear regression procedure with a, a2, b, b2, c and c2 as independent variables. I'm not sure is it a correct way.

from the book refered, only one variable is shown, and it is computed to x and x2. (y=a+bx+cx2)

How about running three variables?

kindly advise.
 

vinux

Dark Knight
#2
I am bit confused.. is a,b,c is your model coefficent or independent variables..

If X,Y &Z are your IVs .. then try with this model

y=a+bx+cx2 +b'y+c'y2+ b"z+c"z2 + dxy + d'xz + d"yz

and eliminate the coeffient if it is not significant.