1. The amount of time spent by North American adults watching television per day

1. 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?
c. What is the probability that, in a random sample of five North American adults, all watch television for more than 7 hours per day?
2. How does mental outlook affect a person’s health? The answer to this question may allow physicians to care more effectively for their patients. In an experiment to examine the relationship between attitude and physical health, Dr. Daniel Mark, a heart specialist at Duke University, studied 1,719 men and women who had recently undergone a heart catheterization, a procedure that checks for clogged arteries. Patients undergo this procedure when heart disease results in chest pain. All of the patients in the experiment were in about the same condition. In interviews, 14% of the patients doubted that they would recover sufficiently to resume their daily routines. Dr. Mark identified these individuals as pessimists; the others were (by default) optimists. After one year, Dr. Mark recorded how many patients were still alive. The data are stored in columns 1 11 = optimist, 2 = pessimist2 and 2 12 = alive, 1 = dead2 . Do these data allow us to infer that pessimists are less likely to survive than optimists with similar physical ailments?
3. An economist working for a state university wanted to acquire information about salaries in publicly funded and private colleges ant universities. She conducted a survey of 623 public, university faculty members and 592 private. university faculty members asking each to report his or her rank (instructor = I, assistant professor = 2, associate professor = 3, and professor and current salary ($1,000). (Adapted from the American Association of University Professors AAUP Annual Report on the Economic Status of the Profession)
a. Conduct a test to determine whether public colleges and universities and private college: and universities pay different salaries when all ranks are combined.
b. For each rank, determine whether there is enough evidence to infer that the private college and university salaries differ from that of publicly funded colleges and universities.
c. If the answers to parts (a) and (b) differ, suggest a cause. d. Conduct a test to determine whether your suggested cause is valid.