Question 1:
(a) The following STATA output (Table 1.1) shows the estimation result when we regress the logarithm of wage (dependent variable) on education and experience (independent variables) for married employees only. Is the model as a whole significant? Please note the relevant statistic and interpret it.
(20 percent)
Table 1.1
Source | SS df MS Number of obs = 2861
-------------+------------------------------ F( 2, 2858) = 399.58
Model | 179.385513 2 89.6927566 Prob > F = 0.0000
Residual | 641.531912 2858 .224468828 R-squared = 0.2185
-------------+------------------------------ Adj R-squared = 0.2180
Total | 820.917425 2860 .287034065 Root MSE = .47378
------------------------------------------------------------------------------
lwage | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
educ | .1045997 .0037199 28.12 0.000 .0973058 .1118936
exper | .0075021 .0008644 8.68 0.000 .0058073 .0091969
_cons | .697136 .0574189 12.14 0.000 .5845494 .8097226
(b) Interpret the slope coefficients. Are they statistically significant?
(40 percent)
(c) Compare the values of R2 and adjusted R2 in the previous STATA output. How are they theoretically related? State the range of their values and explain.
(40 percent)