*******************************************************************
*BELOW IS THE STATA CODE I USED
*******************************************************************

clear;
log using labor, replace t
infile weeks D D2 afqt spouseinc kids ed using labsupply.txt
summarize
regress weeks ed
predict yhat
twoway (scatter weeks ed) (connected yhat ed)
regress weeks kids
log close

********************************************************************

. summarize

    Variable |       Obs        Mean    Std. Dev.       Min        Max
-------------+--------------------------------------------------------
       weeks |      2477    35.80137    20.52091          0         52
           D |      2477     .172386    .3777918          0          1
          D2 |      2477    .4521599    .4978066          0          1
        afqt |      2477    45.24707    26.78621          1         99
   spouseinc |      2477    20.75473    20.07997          0   99.99995
-------------+--------------------------------------------------------
        kids |      2477    .7755349    .4173138          0          1
          ed |      2477    13.18894    2.071381          9         20

. regress weeks ed

      Source |       SS       df       MS              Number of obs =    2477
-------------+------------------------------           F(  1,  2475) =   51.87
       Model |  21402.8631     1  21402.8631           Prob > F      =  0.0000
    Residual |  1021259.41  2475  412.630066           R-squared     =  0.0205
-------------+------------------------------           Adj R-squared =  0.0201
       Total |  1042662.28  2476  421.107543           Root MSE      =  20.313

------------------------------------------------------------------------------
       weeks |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
          ed |   1.419386   .1970811     7.20   0.000     1.032925    1.805847
       _cons |   17.08118    2.63114     6.49   0.000     11.92171    22.24064
------------------------------------------------------------------------------


. regress weeks kids

      Source |       SS       df       MS              Number of obs =    2477
-------------+------------------------------           F(  1,  2475) =  175.04
       Model |  68869.5259     1  68869.5259           Prob > F      =  0.0000
    Residual |  973792.749  2475  393.451616           R-squared     =  0.0661
-------------+------------------------------           Adj R-squared =  0.0657
       Total |  1042662.28  2476  421.107543           Root MSE      =  19.836

------------------------------------------------------------------------------
       weeks |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
        kids |  -12.63792   .9552292   -13.23   0.000    -14.51105   -10.76479
       _cons |   45.60252   .8412174    54.21   0.000     43.95296    47.25208
------------------------------------------------------------------------------