19. The life expectancy of a particular brand of light bulb is normally distributed with a mean of1500 hours and a standard deviation of 75 hours. a. What is the probability that a light bulb will last less than 1350 hours? b. What is the probability that a light bulb will last more than 1700 hours? c. What is the probability that a light bulb will last between 1600 and 1780 hours? d. 22% of the time a light bulb will last more than how many hours? e. If we wanted only 5% of the bulbs to last less than 1200 hours and we can't change the standard deviation, what must the new mean hours become? f. If we wanted only 5% of the bulbs to last less than 1200 hours and we can't change the mean hours, what must the new standard deviation become? 20. A water fountain is designed to dispense a volume of 12.2 oz. with a standard deviation of 0.5OZ. What percentage of cups end up with at least 13 oz.? 65% of the cups contain more than how much water? Find the middle 70% for the amount of water dispensed.