clear;
x=randi(zeros(100,100),100*ones(100,100));
n=[10,50,100];
for ii=1:3
    xx=x(:,1:n(ii));
    xmean=mean(xx,2);    
    figure(ii);
    hist(xmean);
    title(['n= ',num2str(n(ii)),' :mean= ',num2str(mean(xmean))...
    ' :Standard Deviation= ',num2str(std(xmean))]);
    xlim([0,100]);
end
