Omar has a bag of marbles. The bag contains 10 red marbles 5 blue marbles and 1 green marble. He will randomly select 2 marbles from the bag one at a time without replacement. What is the probability that Omar will select a red marble first and then a green marble?

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.