 Usage:  chi = rrstest(x0,x1,y{,score})   
 
 Input:

  x0                     Matrix of maintained regressors. If there is an intercept term 
                         in the regression, x0 should contain a column of ones. 
                         
  x1                     Matrix of regressors under test. 
                         
  y                      Response variable. 
                         
  score                  The desired score function for test. Default value is 
                         score = 1 (Wilcoxon). 
                         Currently implemented score functions are Wilcoxon (score = 1), 
                         Normal (score = 2), and Sign (score = 3) which are 
                         asymptotically optimal for the logistic, Gaussian 
                         and Laplace error models respectively. Values from 
                         (0,1) are possible too. In this case, sign scores 
                         generalized to the quantile given by the value of 
                         score are computed. 
                         
                         
 Output:

  chi                    Test statistic is asymptotically Chi-squared with 
                         cols(x1) degrees of freedom. 
                         
--------------------------------------------------------------
(C) MD*TECH Method and Data Technologies, 17.8.2000
