question

CONFIDENTIAL 21221/BUM2413 QUESTION 1 [7 MARKS] A previous record shows that drivers get an average of 52300 km on a set of Maxim A51 radial tires with a standard deviation of 6400 km. Hoping to improve that figure, the tire company has added a new polymer to the rubber that should help protect the tires from deterioration caused by extreme temperatures. Twenty drivers who tested the new tires have reported getting an average and standard deviation of 54400 km and 5010 km respectively. Assume that the new tire mileage is normally distributed, can the tire company claim that the addition of the new polymer in the new tire produces a more consistent tire mileage? Test at 10% level of significance. [7 Marks]