A professor surveys his students about their opinions on how well he taught the course. He puts this survey on the last page of his final exam. Which type of bias will most likely have the strongest effect on the survey results? -Not all students will have the access needed to find the survey. -Students may not truthfully reply because they fear it will affect their grade. -Students may not understand the wording used in the survey. -Not all students will be represented in the survey sample.

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.