data miller;
input time c grp;
datalines;
   9     1     1
  13     1     1
  13     0     1
  18     1     1
  23     1     1
  28     0     1
  31     1     1
  34     1     1
  45     0     1
  48     1     1
 161     0     1
   5     1     2
   5     1     2
   8     1     2
   8     1     2
  12     1     2
  16     0     2
  23     1     2
  27     1     2
  30     1     2
  33     1     2
  43     1     2
  45     1     2
  ;
  proc lifetest data = miller plots=(s);
  time time*c(0);
  strata grp;
  run;
--------------
                     The SAS System          22:36 Wednesday, May 24, 2000   1

                         The LIFETEST Procedure

                           Stratum 1: grp = 1

                     Product-Limit Survival Estimates

                                       Survival
                                       Standard     Number      Number
      time     Survival    Failure      Error       Failed       Left

     0.000       1.0000           0           0        0          11
     9.000       0.9091      0.0909      0.0867        1          10
    13.000       0.8182      0.1818      0.1163        2           9
    13.000*           .           .           .        2           8
    18.000       0.7159      0.2841      0.1397        3           7
    23.000       0.6136      0.3864      0.1526        4           6
    28.000*           .           .           .        4           5
    31.000       0.4909      0.5091      0.1642        5           4
    34.000       0.3682      0.6318      0.1627        6           3
    45.000*           .           .           .        6           2
    48.000       0.1841      0.8159      0.1535        7           1
   161.000*           .           .           .        7           0

       NOTE: The marked survival times are censored observations.

                Summary Statistics for Time Variable time
                            Quartile Estimates

                            Point     95% Confidence Interval
               Percent    Estimate      [Lower      Upper)

                    75      48.000      31.000        .
                    50      31.000      18.000      48.000
                    25      18.000       9.000      34.000


                           Mean    Standard Error

                         31.843             4.891

   NOTE: The mean survival time and its standard error were underestimated because the largest
       observation was censored and the estimation was restricted to the largest event time.

                      The LIFETEST Procedure

                        Stratum 2: grp = 2

                  Product-Limit Survival Estimates

                                    Survival
                                    Standard     Number      Number
   time     Survival    Failure      Error       Failed       Left

  0.000       1.0000           0           0        0          12
  5.000            .           .           .        1          11
  5.000       0.8333      0.1667      0.1076        2          10
  8.000            .           .           .        3           9
  8.000       0.6667      0.3333      0.1361        4           8
 12.000       0.5833      0.4167      0.1423        5           7
 16.000*           .           .           .        5           6
 23.000       0.4861      0.5139      0.1481        6           5
 27.000       0.3889      0.6111      0.1470        7           4
 30.000       0.2917      0.7083      0.1387        8           3
 33.000       0.1944      0.8056      0.1219        9           2
 43.000       0.0972      0.9028      0.0919       10           1
 45.000            0      1.0000           0       11           0

    NOTE: The marked survival times are censored observations.


             Summary Statistics for Time Variable time

                         Quartile Estimates

                         Point     95% Confidence Interval
            Percent    Estimate      [Lower      Upper)

                 75      33.000      23.000      45.000
                 50      23.000       8.000      33.000
                 25       8.000       5.000      27.000


                        Mean    Standard Error

                      22.708             4.385


      Summary of the Number of Censored and Uncensored Values

                                                          Percent
  Stratum    grp            Total  Failed    Censored    Censored

        1    1                 11       7           4       36.36
        2    2                 12      11           1        8.33

                     The LIFETEST Procedure

     Summary of the Number of Censored and Uncensored Values

                                                         Percent
 Stratum    grp            Total  Failed    Censored    Censored

   Total                      23      18           5       21.74


                     The LIFETEST Procedure

   Testing Homogeneity of Survival Curves for time over Strata


                  Test of Equality over Strata

                                              Pr >
           Test      Chi-Square      DF    Chi-Square

           Log-Rank      3.3964       1      0.0653
           Wilcoxon      2.7233       1      0.0989
           -2Log(LR)     4.0613       1      0.0439