 Usage:  p = aerlb(x1, x2)  
 
 Input:

  x1                     n1 x p matrix (sample 1) 
                         
  x2                     n2 x p matrix (sample2) 
                         
 Output:

  p                      2 x 1 vector, the estimate of the actual error rate (AER) 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
