The average life expectancy of dishwashers produced by Henderson Appliances is 72 months with a standard deviation of 8 months. Assume the lives of these dishwashers are normally distributed. (Throughout the problem, use the number of months.) SKETCH a) What is the probability that a dishwasher will have a life expectancy of at least 60 months?
b) Dishwashers that fail operating in less than 54 months will be replaced free of charge. What percent of dishwashers are expected to be replaced free of charge?
c) what are the minimum and the maximum life expectancy of the middle 95% of the dishwashers' lives? Give your answer in months