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       log:  d:\bill\fall2008\econ30331\state_cig_data_1.log
  log type:  text
 opened on:  25 Sep 2008, 09:14:48

. 
. use state_cig_data

. 
. 
. * generate real taxes
. gen s_rtax=state_tax/cpi

. gen f_rtax=federal_tax/cpi

. gen s_f_rtax=s_rtax+f_rtax

. 
. label var s_rtax "state real tax on cigs, cents/pack"

. label var f_rtax "federal real tax on cigs, cents/pack"

. label var s_f_rtax "state+federal real tax on cigs, cents/pack"

. 
. 
. * construct new variables
. 
. * time trend
. gen trend=year-1981

. 
. * real per capita income
. gen pcir=pci/cpi

. 
. label var trend "=1 in 1st year, 2 in second, etc"

. label var pcir "real per capita income"

. 
. * run regression with tax, real income, trend and two taxes
. * unrestricted model where both taxes enter
. reg packs_pc trend pcir s_rtax f_rtax

      Source |       SS       df       MS              Number of obs =    1020
-------------+------------------------------           F(  4,  1015) =  214.43
       Model |   373614.47     4  93403.6174           Prob > F      =  0.0000
    Residual |  442132.923  1015  435.598939           R-squared     =  0.4580
-------------+------------------------------           Adj R-squared =  0.4559
       Total |  815747.392  1019  800.537186           Root MSE      =  20.871

------------------------------------------------------------------------------
    packs_pc |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       trend |  -1.819112    .154649   -11.76   0.000     -2.12258   -1.515643
        pcir |   .0004883   .0001864     2.62   0.009     .0001226    .0008541
      s_rtax |  -.7979746   .0435066   -18.34   0.000    -.8833477   -.7126015
      f_rtax |  -.2996423   .1930018    -1.55   0.121    -.6783705    .0790858
       _cons |   144.4113   5.477806    26.36   0.000     133.6622    155.1604
------------------------------------------------------------------------------

. 
. *test the hypothesis that the coef is the same
. test s_rtax=f_rtax

 ( 1)  s_rtax - f_rtax = 0

       F(  1,  1015) =    6.40
            Prob > F =    0.0115

. 
. * do the f-test by brute force
. * run the restricted model
. reg packs_pc trend pcir s_f_rtax

      Source |       SS       df       MS              Number of obs =    1020
-------------+------------------------------           F(  3,  1016) =  282.26
       Model |  370824.591     3  123608.197           Prob > F      =  0.0000
    Residual |  444922.802  1016  437.916143           R-squared     =  0.4546
-------------+------------------------------           Adj R-squared =  0.4530
       Total |  815747.392  1019  800.537186           Root MSE      =  20.926

------------------------------------------------------------------------------
    packs_pc |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       trend |  -1.619607   .1334016   -12.14   0.000    -1.881381   -1.357833
        pcir |   .0004559   .0001864     2.45   0.015     .0000901    .0008218
    s_f_rtax |  -.7760163   .0427458   -18.15   0.000    -.8598965   -.6921361
       _cons |   154.4029   3.807324    40.55   0.000     146.9318     161.874
------------------------------------------------------------------------------

. 
. 
end of do-file

. log close
       log:  d:\bill\fall2008\econ30331\state_cig_data_1.log
  log type:  text
 closed on:  25 Sep 2008, 09:15:18
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