People leaving the library were asked how many books they checked out that day. The results are:
1, 2, 3, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20
Which histogram correctly shows the data set?
Books Checked Out
10
8
6
O
Number of people
4
0-5 6-11 12-1718-23
Number of books
Books Checked Out
10
8
6
O
B.
Number of people
2

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.