HYPOTHESIS TEST
A dealer advertises that a certain brand of tire averages 50,000
miles of use before needing to be replaced. Testing this claim, an
investigator finds that a sample of 19 randomly selected tires from
this dealer had an average lifespan of 48,700 miles with a standard
deviation of 4,500 miles. Assume tire life spans are approximately
normally distributed. At the α = 0.05 level, find if the
investigator can prove the dealer is exaggerating the average
lifespan of their tires by performing the hypothesis test.
