Emilia has a bag of colored marbles. the bag contains the same ratio of red marbles to blue marbles as the ratio of green marbles to orange marbles. she has 18 red marbles, 48 blue marbles, and 12 green marbles. how many orange marbles are in the bag? a. 32 b. 28 c. 5 d. 72

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.