Q4. The qualities of two brands of car tires are compared by road-testing samples of n1=n2=100 tires each type. The number of miles until the wearout is given below: Brand A Brand B X, = 26,400 miles X2 = 25,100 miles $2 =1,440,000 $2 =1,960,000 Estimate the difference in mean miles to wearout, using a 99% confidence interval. Is there a difference in the average wearing quality