Suppose the summer daily demand for water use in Phoenix is normally distributed with a mean of 310 million gallons/day and a standard deviation of 45 million gallons/day. Also suppose the city has reservoirs whose combined storage is 350 million gallons.
a. What is the probability that a day requires more water than is stored in city reservoirs?
b. What reservoir capacity is needed so that the probability that it is exceeded is 1%?
c. What amount of water use is exceeded with 95% probability?