 Usage:  surv = hazsurv(data,z)  
 
 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                      n x p matrix, the covariates. 
                         
 Output:

  surv                   n x 2 matrix, the first column is the sorted 
                         t, followed by the estimated survival function 
                         at the points of t, conditional on z. 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
