Consider the following sample regressions for the linear, the quadratic, and the cubic models along with their respective R2 and adjusted R2. Linear Quadratic Cubic
Intercept 29.83 29.35 26.88
x −0.04 0.16 2.11
x2 NA −0.02 −0.38
x3 NA NA 0.02
R2 0.001 0.001 0.008
Adjusted R2 −0.026 −0.053 −0.075
a. Predict y for x = 1 and 2 with each of the estimated models.
b. Select the most appropriate model.
1. Linear model
2. Cubic model
3. Quadratic model