A taxi company is trying to decide whether to purchase brand A or brand B tires for its fleet of taxis. To estimate the difference in the two​ brands, an experiment is conducted using 8 of each​...

A taxi company is trying to decide whether to purchase brand A or brand B tires for its fleet of taxis. To estimate the difference in the two​ brands, an experiment is conducted using
8of each​ brand, assigned at random to the left and right rear wheels of 8 taxis. The tires are run until they wear out and the​ distances, in​ kilometers, are recorded in the accompanying data set. Find a 99​% confidence interval for μ1−μ2. Assume that the differences of the distances are approximately normally distributed.

Brand A:  X₁
=  35100     S₁
= 4800

Brand B:  X₂
=  38200     S₂
= 6600