% MS-A0503 L3A demo
% Room counts in households, taking a sample of two households.
% (Matlab code)
px = [.5 .2 .1 .1 .1];
py = px;        % same distribution

% Find out the probabilities for X+Y=s,
% for all possible values of s.
ps = zeros(1,10);
for s=2:10
    % What are the choices for x+y = s?
    for x=1:5
        y = s-x;
        if y>=1 && y<=5
            ps(s) = ps(s) + px(x)*py(y);
        end
    end
end

subplot(1,3,1)
bar(1:5,px)
xlabel('x')

subplot(1,3,2)
bar(1:5,py)
xlabel('y')

subplot(1,3,3)
bar(1:10,ps)
xlabel('s')