n = [2 5 10 50 100 1000];
k=50000;
mu = 1;sigma=1.6;
for i = 1:6
  X = exp(normrnd(mu,sigma,n(i),k));
  m = mean(X);
  s = std(X);
  subplot(2,3,i);
  z = 0:0.025:50;
  y = histc(s,z)/k;
  bar(z,y,1);
  %axis([0 16 0 0.015]);
  str = sprintf('n= %d',n(i));
  title(str);
end
