Tim is selling tickets to a school sporting event to raise money for his club. he puy extra money in the box before he began. as he sells tickets, he records the number of tickets he has sold and the total amount of money in the box. some of his data are shown below. ( explain how you got the i have major

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.