How easy is it to get into contact with a person in Sacramento, California? If you don't know the telephone number, it could be difficult. The date from Survey Sampling of Fairfield Connecticut reported in American Demographics, show that 68% of the telephone-owning households in Sacramento have unlisted numbers. For a random sample of 150 Sacramento households with telephone, what is the probability that
a. 100 or more have unlisted numbers?
b. Fewer than 100 have unlisted numbers?
c. Between 50 and 65 (including 50 and 66) households have listed numbers?