6. The grades on an examination whose mean is 525 and whose standard deviation is 80 are normally distributed. What is the probability that the person will score the examination below than 350 ? 7. For a car traveling 30 miles per hour (mph), the distance required to brake to a stop is normally distributed with a mean of 50 feet and a standard deviation of 8 feet. Suppose you are traveling in a residential area and a car abruptly into your path at a distance of 60 feet. What is the probability that you will (a) brake a stop within 40 feet or less ? (b) Brake a stop between 40 feet and 45 feet ? 8. Suppose that you must establish regulations concerning the maximum number of people who can occupy an elevator. A study of elevator occupancies indicates that if eight people occupy the elevator, the probability distribution of the total weight of the eight people has a mean equal to 1200 pounds and a standard deviation of 99 pounds. What is the probability that the total weight of eight people exceeds 1300 pounds