function Z=rvtail(X, k, pf) 
% rvtail(X, k, pf) Generates a column vector containing the percentage of 
%                  times the samples in each experiment in the random 
%                  variable matrix X was more than k standard deviations  
%                  away from the expected mean.  For good result, pf should 
%                  be the probability function associated with X. 
if k<0 
   error('k < 0') 
end 
r=k*sqrt(var(pf)); 
M=size(X); 
Z=zeros(M(1),1); 
u=mmean(pf); 
for i=1:M(1), 
   for j=1:M(2), 
      if ~(inrange(X(i,j),u,r)) 
         Z(i)=Z(i)+1; 
      end 
   end 
end 
Z=Z./M(2);