Question: a. Now someone claims that the effect of age on education is non-linear. Briefly support this conjecture. No statistical language is necessary.

b. Fit the model including the squared term of this variable. Do not include the interaction term you examined in 8.101 above. Show the estimated equation. Test whether the squared term can be dropped from the model at the .05 level. State the alternative, decision rule, p-value, and conclusion.

Is this effect of the squared term “meaningful?” Briefly explain why or why not.

c. Suppose that we retained this squared term. For a male who is the only child, show the estimated equation in a graphic form (second-order polynomial response).