 Usage:  {bhaz, bsurv} = hazbase(data)  
 
 Input:

  data                   n x (p+4) matrix, the first column is the sorted 
                         survival time t, followed by the sorted delta, 
                         inidcating if censoring has occured, labels l, a 
                         column containing the number of ties, and lastly, 
                         the sorted covariate matrix z. 
                         
 Output:

  bhaz                   n x 2 matrix, the first column is the sorted 
                         t, followed by the estimated baseline hazard 
                         function at the points of t. 
                         
  bsurv                  n x 2 matrix, the first column is the sorted 
                         t, followed by the estimated baseline survival 
                         function at the points of t. 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
