7. Consider the following regression estimates (robust standard errors in parentheses): 1wage = 1.251 - 0.0036 educ + 0.0029 educ2 (0.122) (0.0249) (0.0012) 0.0791 educ x female + 0.0039 educ? x female. (0.0178) (0.0013) Here, 1wage is the logarithm of hourly wage, educ is educational attainment measured in years, and female is a binary variable representing women in the sample. As usual, we will call the above estimated coefficients by Bo, Bi, . .., BA. (a) What is the estimated marginal effect of education for someone who already has 16 years of education? (Please answer this question for men and women separately). (3 points) (b) Based on the estimated regression coefficients, does education have an increasing, constant, or decreasing return to income? Would your answer be different for men and women? (2 points) (c) A researcher tries to test the hypothesis that Ho : B2 = B4 = 0. Interpret this hypothesis. Conduct a Bonferroni test at the 5% level using the p-value approach. (3 points) (d) Consider the hypothesis Ho : B3 = B4 = 0. Interpret this hypothesis. It is found that the F statistic is 20.13. Would you reject the hypothesis at the 1% level? (2 points)