 Usage:  {data,ties} = hazdat(t, delta {,z})  
 
 Input:

  t                      n x 1 vector, the censored survival time. 
                         
  delta                  n x 1 vector, the censoring indicator, showing 
                         if censoring occured (0) or not (1). 
                         
  z                      n x p matrix of covariates. 
                         
 Output:

  data                   n x (p+4) matrix, the first column is the sorted 
                         t, followed by the sorted delta, labels l, a 
                         column containing the number of ties, 
                         and lastly, the sorted covariate matrix z. 
                         
  ties                   a scalar equaling either 1 (there are ties) or 0 
                         (there are no ties) 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
