1.Using the regression results in column (2) of the following table

a.Is age an important determinant of earnings? Use an appropriate statistical test and or confidence interval to explain your answer.

b.Sally is a 29-year-old female college graduate. Betsy is a 34-year-old female college graduate. Construct a 95% confidence interval for the expected difference between their earnings.

Results of Regressions of Average Hourly Eamings on Gender and Education Binary Variables and Other Characteristics Using 1998 Data from the Current Population Survey Dependent Variable: average hourly earnings (AHE). Regressor (1) (2) (3) College (X1) 5.46 5.48 5.44 (0.21) (0.21) (0.21) Female (X2) -2.64 -2.62 -2.62 (0.20) (0.20) (0.20) Age (X3) 0.29 0.29 (0.04) (0.04) Northeast (X4) 0.69 (0.30) Midwest (X5) 0.60 (0.28) South (X6) -0.27 (0.26) Intercept 12.69 4.40 3.75 (0.14) (1.05) (1.06) Summary Statistics and Joint Tests F-statistic for regional effects = 0 6.10 SER 6.27 6.22 6.21 R2 0.176 0.190 0.194 n 4000 4000 4000