A taxi company is trying to decide: whether to purchase brand .4 or brand B tires for its fleet of taxis. To estimate the difference in the two brands, an experiment is conducted using 12 of each brand. The tires are run until they wear out. The results are 

Brand .4:         x₁ – 36,300 kilometers,

                         s₁ = 5,000 kilometers.

Brand B:          x₂ = 38,100 kilometers,

                          s₂ = 6.100 kilometers.

Compute a 95% confidence interval for μ_A — pa assuming the populations to be approximately normally distributed. You may not assume that the variances are equal.