12-22. Two brands of heavy duty fan belts (call them brand X and brand Y)

have about the same average durability. However, their uniformity of wear is questionable. A sample of 10 brand X belts and 15 brand Y belts yielded s2X

= 5.576 (miles)2 and s2Y

= 8.025 (miles)2, respectively. Should a trucking company purchase brand X belts for its fleet of trucks? Use

α = 0.05.