3. The mean and standard deviation of the lifetime of a car muffler manufactured by company A are 5 and 2 years, respectively. These quantities for car mufflers manufactured by company B are, respectively, 4 years and 18 months. Brian buys one muffler from company A and one from company B. That of company A lasts 4 years and 3 months, and that of company B lasts 3 years and 9 months. Determine which of these mufflers has performed relatively better. Hint: Find the standardized lifetimes of the mufflers and compare (see Section 4.6).