An automotive company is considering two types of batteries for its automobile. Sample information on the life of the battery is collected for 20 batteries of type A and 20 batteries of type B. The...

An automotive company is considering two types of batteries for its automobile. Sample information on the life of the battery is collected for 20 batteries of type A and 20 batteries of type B. The summary statistics are XA = 40.21, xB = 39.53, SA = 1.23, and SB= 1.59. Assume the data on each battery are normally distributed and assume σA = σB.
(a) Find a 95% confidence interval on μA – μB.
(b) Draw some conclusion from (a) that provides some insight into whether A or B should be adopted.