According to JAVMA News, a publication of the American Veterinary Medical Association, roughly 60% of U.S. households own one or more pets. Four U.S. households are selected at random. Use Table XI in Appendix A to solve the following problems.

a. Find the probability that, of the four households sampled, the number that own one or more pets is exactly three; at least three; at most three.

b. Find the probability distribution of the random variable X, the number of U.S. households in a random sample of four that own one or more pets.

c. Without referring to the probability distribution obtained in part (b) or constructing a probability histogram, decide whether the probability distribution is right skewed, symmetric, or left skewed. Explain your answer.