2/3 of a hippos life is spent under water, the rest of their life out of water is separated into grazing, sleeping and
socialising in the ratio 4 : 7 : 1. The average life of a hippo is
45years, how long will it spend doing each of these
activities?

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.