The Monday after Thanksgiving is called Cyber Monday. Amazon is offering deals on many popular items. The same drone helicopter
is normally sold for $179.99, but on Cyber Monday, Amazon will be
selling it for $125.99. What is the percent change on the drone. Round to the nearest percent

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.