Different groups of 50 graduates of an engineering school were asked the
starting annual salary for their first engineering job after graduation, and the
sampling variability was low. if the average salary of one of the groups was
$65,000, which of these is least likely to be the average salary of another of
the groups?

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.