/* PubH 7450
Exampel 7.6b: Four-sample tests using the larynx cancer data, as compared
              to the trend tests. 
*/

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 ;

proc lifetest method=km plots=(s);
strata stage / test=(logrank wilcoxon tarone peto modpeto
                     fleming(.5,2) );
time time*status(0) ;

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

          Testing Homogeneity of Survival Curves for time over Strata

                                Rank Statistics

                                                            Modified
stage       Log-Rank    Wilcoxon      Tarone        Peto        Peto     Fleming

1            -7.5660     -579.00      -65.50     -6.3700     -6.2810     -0.1979
2            -3.0117     -223.00      -25.88     -2.4550     -2.4225     -0.0872
3             2.9155      244.00       26.33      2.6306      2.5939     -0.0128
4             7.6623      558.00       65.05      6.1944      6.1097      0.2979


                 Covariance Matrix for the Log-Rank Statistics

         stage             1             2             3             4

         1           12.0740       -4.4516       -6.2465       -1.3759
         2           -4.4516        7.8730       -2.7599       -0.6614
         3           -6.2465       -2.7599        9.9302       -0.9238
         4           -1.3759       -0.6614       -0.9238        2.9612


                 Covariance Matrix for the Wilcoxon Statistics

         stage             1             2             3             4

         1           47646.5      -16704.9      -23211.0       -7730.6
         2          -16704.9       31507.4      -11029.6       -3773.0
         3          -23211.0      -11029.6       39639.2       -5398.6
         4           -7730.6       -3773.0       -5398.6       16902.2



                  Covariance Matrix for the Tarone Statistics

         stage             1             2             3             4

         1           702.438      -251.984      -348.764      -101.690
         2          -251.984       462.730      -161.439       -49.308
         3          -348.764      -161.439       579.900       -69.697
         4          -101.690       -49.308       -69.697       220.695


                   Covariance Matrix for the Peto Statistics

         stage             1             2             3             4

         1           6.22278      -2.20787      -3.08231      -0.93260
         2          -2.20787       4.09747      -1.43558      -0.45402
         3          -3.08231      -1.43558       5.16677      -0.64888
         4          -0.93260      -0.45402      -0.64888       2.03550

              Covariance Matrix for the Modified Peto Statistics

         stage             1             2             3             4

         1           6.01900      -2.13350      -2.97718      -0.90833
         2          -2.13350       3.96465      -1.38886      -0.44229
         3          -2.97718      -1.38886       4.99835      -0.63232
         4          -0.90833      -0.44229      -0.63232       1.98294


                 Covariance Matrix for the Fleming Statistics

         stage             1             2             3             4

         1          0.153156      -.059613      -.090146      -.003398
         2          -.059613      0.096244      -.035144      -.001487
         3          -.090146      -.035144      0.127261      -.001971
         4          -.003398      -.001487      -.001971      0.006856


                          Test of Equality over Strata

                 Test          Chi-Square      DF    Chi-Square

                 Log-Rank         22.7628       3      <.0001  
                 Wilcoxon         23.1770       3      <.0001  
                 Tarone           23.1407       3      <.0001  
                 Peto             23.1711       3      <.0001  
                 Modified Peto    23.1703       3      <.0001  
                 Fleming(0.5,2)   12.9818       3      0.0047