Question: Suppose that Dunlop Tire manufactures tires having the property that the mileage the tire lasts approximately follows a normal distribution with a mean of 70,000 miles and a standard deviation of 4,400 miles.

a. Dunlop warrants its tires for 60,000 miles. what proportion of the tires will last 60,000 miles or less?
b. What is the probability that a randomly selected Dunlop tire lasts between 65,000 and 80,000 miles?
c. Suppose that dunlop wants to warrant no more than 2% of its tires. What mileage should Dunlop advertise its warranty mileage?