Suppose you fit the quadratic model E(y) = 0 + 1x + 2x2 To a set of n = 20 data points and find that

Suppose you fit the quadratic model

E(y) = β0 + β1x + β2x2

To a set of n = 20 data points and find that R2 = .91, SSyy = 29.94, and SSE = 2.63.

a. Is there sufficient evidence to indicate that the model contributes information relevant to predicting y? Test using α = .05.

b. What null and alternative hypotheses would you test to determine whether upward curvature exists?

c. What null and alternative hypotheses would you test to determine whether downward curvature exists?