In 1987 a recording artist sold 14,000 albums. in 1998 that same artist sold 4,683 albums. find the rate of change in record sales from 1987 to 1998. a. 1/847 years per album. b. –847 albums per year. c. 847 albums per year. d. –847 years per album.

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.