Question: The R.R. Bowker Company of New York collects information on the retail prices of books and publishes its findings in The Bowker Annual Library and Book Trade Almanac, In 2000, the mean retail price of all history books was USD 51.46. This year's retail prices for 40 randomly selected history books are shown in the table below.
|
56
|
46.25
|
47.34
|
53.99
|
|
53.71
|
47.88
|
54.82
|
55.73
|
|
51
|
61.70
|
47.03
|
62.68
|
|
47.80
|
50.89
|
52.36
|
50.95
|
|
51.28
|
50.94
|
60.70
|
72.38
|
|
47.70
|
56.16
|
52.33
|
51.70
|
|
53.8
|
50.90
|
63.74
|
52.87
|
|
41.08
|
64.93
|
57.44
|
54.09
|
|
75.37
|
56.48
|
69.04
|
42.71
|
|
53.76
|
72.17
|
61.26
|
42.65
|
At the 5 percent significance level, do the data provide sufficient evidence to conclude this year's mean retail price of all history books has increased from the 2000 mean of USD 51.46?
Calculate the value of the test statistic. (You may suppose that the sample standard deviation of prices for this year's history books is USD 7.61.)