1. 12 ducks fly overhead. Each of 6 hunters picks one duck at random to aim at and kills it with probability 0.6. (a) What is the mean number of ducks that are killed? (b) What is the expected number of hunters who hit the duck they aim at?
2. Suppose Noah started with n pairs of animals on the ark and m of them died. If we suppose that fate chose the m animals at random, what is the expected number of complete pairs that are left?
3. Roll two dice and let Z = X Y be the product of the two numbers obtained. What is the mean and variance of Z?
4. Let Nk be the number of independent trials we need to get k successes when success has probability p. Find the mean and variance of Nk.
5. Let X = binomial(4, 1/2). Use Chebyshev's inequality to estimate P (I X -21 > 2) and compare with the exact probability.
6. Let X have a Poisson distribution with mean 16. Estimate P( X > 28) using (a) Chebyshev's inequality and (b) the normal approximation.
7. Suppose we toss a coin 100 times. Which is bigger, the probability of exactly 50 heads or at least 60 heads?
8. In a 162-game season find the approximate probability that a team with a 0.5 chance of winning will win at least 87 games.