Maria spends 910 hours on her art project. Juan spends 26 hours on his art project. Which answer is the most accurate estimate for how much more time Maria spends on her art project than Juan spends on his? A 0 hours B12 hour C34 hour D1 hour

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.