Flip a coin thrice (3 times), and let X and Y denote the number of heads in the first two flips, and in the last two flips, respectively. For example, if the coins turn up h, h,t then X=2 and Y=1, while if they turn up t, t,h then X=0 and Y=1. Find: 1. Cov(X, Y),
2. rho X, Y.