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 36 teenage boys was $677. for 23 teenage girls, it was $554. 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 for auto insurance for teenage boys is greater than that for teenage girls. conduct a hypothesis test at the 5% level