6.23 Elevator Capacities Suppose you must establish regulations concerning the maximum number of people who can occupy an elevator. Suppose a study of elevator occupancies indicates that, if eight people occupy the elevator, the probability distribu- tion of the total weight of the eight people has a mean equal to 550 kg and a variance equal to 445 kg. What is the probability that the total weight of eight people exceeds 590 kg? 680 kg? (Assume that the probability distribution is approximately normal.)