Which best explains why students who can solve problems create better projects? They complete assignments on time by asking their teacher for solutions.
They develop a better understanding because they work by themselves.
They complete assignments by motivating others to do the work for them.
They develop a better understanding because they are actively engaged.

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.