/* PubH 7450
Exampel 12.2b: fitting a PHM using the larynx cancer data;
              comparing it to the fitted Weibull AFT model.
              comparing to Tables 12.1 and 12.2 on p.400. 
*/

options ls=80 center pagesize=60 number label;
goptions device = PS;  
         /* graphs are saved in a file names sasgraph.ps */

data larynx;
infile '/home/merganser/weip/public_html/course/7450/data/larynx.txt'
       firstobs=19;
input stage time age year status ;
  if stage=2 then Z1=1;
     else Z1=0;
  if stage=3 then Z2=1;
     else Z2=0;
  if stage=4 then Z3=1;
     else Z3=0;

proc phreg;
model time*status(0) = Z1 Z2 Z3 age ;

**********************Output:

                             Model Fit Statistics
 
                                     Without           With
                    Criterion     Covariates     Covariates

                    -2 LOG L         394.426        376.359
                    AIC              394.426        384.359
                    SBC              394.426        392.007


                    Testing Global Null Hypothesis: BETA=0
 
            Test                 Chi-Square       DF     Pr > ChiSq

            Likelihood Ratio        18.0670        4         0.0012
            Score                   24.3274        4         <.0001
            Wald                    20.8256        4         0.0003


                    Analysis of Maximum Likelihood Estimates
 
                   Parameter     Standard                               Hazard
  Variable   DF     Estimate        Error   Chi-Square   Pr > ChiSq      Ratio

  Z1          1      0.13842      0.46232       0.0896       0.7646      1.148
  Z2          1      0.63815      0.35609       3.2116       0.0731      1.893
  Z3          1      1.69333      0.42218      16.0876       <.0001      5.438
  age         1      0.01890      0.01425       1.7589       0.1848      1.019