The amount of time spent by North American adults watching television per day is normally distributed with a mean of 6 hours and a standard deviation of 1.5 hours.
a) What is the probability that a randomly selected North American adult watches television for more than 7 hours per day?
b) What is the probability that the average time watching television by a random sample of five North American adults is more than 7 hours per day?
c) What is the probability that in a random sample of 5 North American adults, all watch television for more than 7 hours per day?