% we have 500 balls in the urn
M  = 500;   
%we extract 3 balls, one at a time, without replacement
n  = 3;     
%initially, in the urn we have 250 red and 250 white balls
K  = M/2;   
% red balls are ten times more likely to be extracted than the white balls
odds  = 10;    
% We compute the cumulative probability of getting 2 red balls (in drawing
% the 2 balls without replacement).
x = 2;
wcdf = WNChygecdf(x,M,K,n,odds);
disp('See WNChygecdf;');
disp(wcdf);