Parents of teenage boys often complain that auto insurance costs more, on average, for teenage boys than for teenage girls. A group of concerned parents examines a random sample of insurance bills. The mean annual cost for 58 teenage boys was $680, and it was $560 for 58 teenage girls. From past years, it is known that the population standard deviation for each group is $180. Determine whether or not you believe that the mean cost of auto insurance for teenage boys is greater than that for teenage girls (H0 is null hypothesis, and Ha is alternative hypothesis). If you conduct hypothesis testing, you have to consider: