The football team needs a combined total of 168 T-shirts for field day. The number of extra large T-shirts needed is three times the number of large T-shirts needed. Based on this information, would it be reasonable for the football coach to order 40 large T-shirts and 128 extra large T-shirts?​

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.