The manufacturer of the X15 steelbelted radial truck tire cl

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. Assume the mileage wear follows the normal distribution and the population standard deviation of the distribution is 5,000 miles. Crosset Truck Company bought 48 tires and found that the mean mileage for its trucks is 59,500 miles. Crosset would like to know if their experience is different from the manufacturer

Solution

H0: x bar = mu

Ha: xbar not equals mu

Two tailed test

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t statistic = -0.6928

p value = 0.4918