Suppose that 40% of all U.S. employees contribute to a retirement plan (p = .40).
a. In a random sample of 100 employees, what is the approximate probability that at least half of those in the sample contribute to a retirement plan?
b. Suppose you were told that at least 60 of the 100 employees in a sample from your state contribute to a retirement plan. Would you think p = .40 for your state? Explain.