The manufacturer of the X-15 steel-belted radial truck tire claims that the mean mileage the tire
can be driven before the tread wears out is 60,000 miles. The standard deviation of the mileage is
5,000 miles. The Crosset Truck Company bought 48 tires and found that the mean mileage for
their trucks is 59,500 miles. Is Crosset's experience different from that claimed by the manufacturer
at the .05 significance level?
The solution contains detailed explanation of testing hypotheses using the five-step procedure.