-------------------------------------------------------------------------------------------------
       log:  C:\MyDocs\MPH\Text\SecondEdition\WebDoFiles\8.12.Framingham.log
  log type:  text
 opened on:   3 Jan 2008, 17:35:21

. *  8.12.Framingham.log                
. *
. *  Analysis of the effects of gender and body mass index
. *  on coronary heart disease using person-year data from the
. *  Framingham Heart Study.
. *
. use C:\WDDtext\8.12.Framingham.dta, clear

. *
. *  Regress CHD against gender using model 8.9.
. *
. poisson chd_cnt male, exposure(pt_yrs) irr

Iteration 0:   log likelihood = -1841.3761  
Iteration 1:   log likelihood = -1841.3756  
Iteration 2:   log likelihood = -1841.3756  

Poisson regression                                Number of obs   =       1267
                                                  LR chi2(1)      =     134.30
                                                  Prob > chi2     =     0.0000
Log likelihood = -1841.3756                       Pseudo R2       =     0.0352

------------------------------------------------------------------------------
     chd_cnt |        IRR   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
        male |   1.832227   .0961444    11.54   0.000     1.653154    2.030698
      pt_yrs | (exposure)
------------------------------------------------------------------------------

. table bmi_gr, contents(sum pt_yrs sum chd_cnt) row

--------------------------------------
   bmi_gr |  sum(pt_yrs)  sum(chd_cnt)
----------+---------------------------
     22.8 |        27924           239
     25.2 |        26696           337
       28 |        26729           443
       29 |        22977           453
          | 
    Total |       104326          1472
--------------------------------------

. *
. *  Regress CHD against BMI using model 8.10.
. *
. xi: poisson chd_cnt i.bmi_gr, exposure(pt_yrs) irr
i.bmi_gr          _Ibmi_gr_1-4        (_Ibmi_gr_1 for bmi~r==22.79999923706055 omitted)

Iteration 0:   log likelihood = -1837.8278  
Iteration 1:   log likelihood = -1837.5817  
Iteration 2:   log likelihood = -1837.5816  

Poisson regression                                Number of obs   =       1234
                                                  LR chi2(3)      =     131.76
                                                  Prob > chi2     =     0.0000
Log likelihood = -1837.5816                       Pseudo R2       =     0.0346

------------------------------------------------------------------------------
     chd_cnt |        IRR   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
  _Ibmi_gr_2 |   1.474902    .124727     4.60   0.000     1.249627    1.740789
  _Ibmi_gr_3 |   1.936424   .1554146     8.23   0.000     1.654567    2.266297
  _Ibmi_gr_4 |    2.30348   .1841575    10.44   0.000     1.969396    2.694237
      pt_yrs | (exposure)
------------------------------------------------------------------------------

. log close
       log:  C:\MyDocs\MPH\Text\SecondEdition\WebDoFiles\8.12.Framingham.log
  log type:  text
 closed on:   3 Jan 2008, 17:35:21
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