Two brands of car batteries, both carrying 6-year warranties, were sampled and tested under controlled conditions, Five of each brand failed after the number of months shown. Calculate a) both sample means and b) both sample standard deviations. Decide c) which brand battery lasts longer and d) which brand has the more consistent lifetime. Brand A: 76,70,65,65,66 Brand B: 70,66,61,72,67 a) What are the sample means? xA=xB=