 Usage:  {bcumhaz, bsurv} = hazcoxb(data)  
 
 Input:

  data                   n x (p+4) matrix, 
                         column 1: the sorted observed survival time t, 
                         column 2: the cosorted censoring indicator delta, 
                         column 3: labels l, 
                         column 4: number of ties at time t[i], cosorted, 
                         columns 5 to p+4: the cosorted covariate matrix z. 
                         
 Output:

  bcumhaz                n x 2 matrix, 
                         column 1: the sorted observed survival time t, 
                         column 2: estimated cumulative baseline hazard 
                         function at the points of t. 
                         
  bsurv                  n x 2 matrix, 
                         column 1: the sorted observed survival time t, 
                         column 2: estimated baseline survival 
                         function at the points of t. 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
