A dishwasher has a mean lifetime of 11 years with an estimated standard deviation of 2 years. Assume the lifetime of a dishwasher is normally distributed.

d) Use the Empirical Rule to approximate the percentage of dishwashers that last between 9 years and 13 years.

e) If the warranty guarantees the dishwasher will last at least 9 years or your money back, what is the probability that the company will have to refund money to a customer?