n = [2 3 5 10 20 30];
k=50000;
mu = 8.25;sigma=0.75;
for i = 1:6
 X = normrnd(mu,sigma,n(i),k);
 m = mean(X);
 subplot(2,3,i);
 z = 6.5:0.02:10;
 y = hist(m,z)/k;
 bar(z,y,1);
 axis([6.5 10 0 0.1]);
 str = sprintf('n= %d',n(i));
 title(str);
end
