 Usage:  {t,p} = hhtest(vhat,y,yhat,h,{c,{m}})  
 
 Input:

  vhat                   n x 1 matrix with the projected index 
                         
  y                      n x 1 matrix 
                         
  yhat                   n x 1 matrix with the parametric estimate of E(Y|X) 
                         
  h                      scalar (positive) -- the bandwidth for kernel 
                         regression with Quartic kernel 
                         
  c                      scalar 0 =< c < 1 (optional) -- proportion of the 
                         sample to be cut in each extreme. Default is 0.05. 
                         
  m                      n x 1 or the scalar 1. m should be given only for 
                         binary responses. If the data is binomial m is the 
                         vector with the binomial coeficients. If the data is 
                         bernouli, m=1. m is necessary to calculate the vari- 
                         ance of y. If y is not binary the variance will be 
                         given by a nonparametric regression of (y-fhat)^2 
                         on vhat. 
                         
 Output:

  t                      scalar -- the statistic value 
                         
  p                      scalar -- the p-value of t 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
