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       log:  d:\bill\fall2008\econ30331\ed_attain.log
  log type:  text
 opened on:  25 Sep 2008, 14:35:07

. use ed_attain

. 
. 
. 
. * generate student teacher ratio
. gen pupil_staff=enroll/staff

. label var pupil_staff "pupil staff ratio"

. 
. * run unrestricted model
. reg droprate lnchprg pupil_staff salary benefit expend

      Source |       SS       df       MS              Number of obs =     408
-------------+------------------------------           F(  5,   402) =    5.13
       Model |   734.13002     5  146.826004           Prob > F      =  0.0001
    Residual |    11510.88   402  28.6340299           R-squared     =  0.0600
-------------+------------------------------           Adj R-squared =  0.0483
       Total |  12245.0101   407  30.0860198           Root MSE      =  5.3511

------------------------------------------------------------------------------
    droprate |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     lnchprg |   .0986281   .0214838     4.59   0.000     .0563935    .1408627
 pupil_staff |   .0057106   .0117324     0.49   0.627     -.017354    .0287752
      salary |  -.0000206   .0000876    -0.23   0.814    -.0001928    .0001516
    benefits |   -.000077   .0002259    -0.34   0.733    -.0005211    .0003671
      expend |   .0004369    .000458     0.95   0.341    -.0004635    .0013372
       _cons |   1.666554   2.261232     0.74   0.462    -2.778764    6.111871
------------------------------------------------------------------------------

. 
. * test that purchased inputs are all zero
. test pupil_staff salary benefits expend

 ( 1)  pupil_staff = 0
 ( 2)  salary = 0
 ( 3)  benefits = 0
 ( 4)  expend = 0

       F(  4,   402) =    0.34
            Prob > F =    0.8489

. 
. * run the brute force ftest
. * unrestricted model is one without 
. * purchased inputs
. reg droprate lnchprg 

      Source |       SS       df       MS              Number of obs =     408
-------------+------------------------------           F(  1,   406) =   24.42
       Model |  694.854867     1  694.854867           Prob > F      =  0.0000
    Residual |  11550.1552   406  28.4486581           R-squared     =  0.0567
-------------+------------------------------           Adj R-squared =  0.0544
       Total |  12245.0101   407  30.0860198           Root MSE      =  5.3337

------------------------------------------------------------------------------
    droprate |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     lnchprg |    .096004   .0194255     4.94   0.000     .0578168    .1341912
       _cons |    2.64698    .556227     4.76   0.000     1.553535    3.740424
------------------------------------------------------------------------------

. 
. * is this a problem of multicollinearity
. corr pupil_staff salary benefits expend
(obs=408)

             | pupil_~f   salary benefits   expend
-------------+------------------------------------
 pupil_staff |   1.0000
      salary |   0.5100   1.0000
    benefits |   0.3113   0.5667   1.0000
      expend |   0.3115   0.6503   0.4714   1.0000


. 
. 
end of do-file

. sum droprate lnchprg pupil_staff salary benefit

    Variable |       Obs        Mean    Std. Dev.       Min        Max
-------------+--------------------------------------------------------
    droprate |       408    5.066422    5.485072          0       61.9
     lnchprg |       408    25.20147    13.61008        1.4       79.5
 pupil_staff |       408    26.94982    26.32721   1.388206   157.9592
      salary |       408    31774.51    5038.304      19764      52812
    benefits |       408    6463.429    1456.338          0      11618

. log close
       log:  d:\bill\fall2008\econ30331\ed_attain.log
  log type:  text
 closed on:  25 Sep 2008, 14:36:07
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