In: Math
A poker hand (5 cards) is dealt off the top of a well-shuffled deck of 52 cards. Let X be the number of diamonds in the hand. Let Y be the number of hearts in the hand.
1. Do you think Cov[X,Y] is positive, negative, or zero? Explain.
2. let Di(i=1,...,5) be a random variable that is 1 if the ith card is a diamond and 0 otherwise. What is E[Di]?
3. let Hi(i=1,...,5) be a random variable that is 1 if the ith card is a heart and 0 otherwise. Of course, E[Hi] is the same as E[Di], since there are the same number of hearts as diamonds in a 52-card deck. What is Cov[Di,Hi]? What is Cov[Di,Hj], when i≠j?
4. Use your answers to parts 2 and 3 (and the properties of covariance, of course) to calculate Cov[X,Y].