Can students save money by shopping for textbooks at Amazon.com? To investigate this possibility, a random sample of textbooks used last semester at a local university was selected. The prices for these textbooks at the university bookstore and through Amazon.com were recorded (see list below) .
The study was confined to two populations of interest: textbooks used in humanities courses taught at the university, and textbooks used in hard sciences courses taught at the university. The data are is below, where variable Type is '1' for Humanities and '2' for Hard Science books.
Based on the data from this study, the following questions need to be answered about the underlying population:
I. Can we be reasonably sure that, at the university bookstore, the average price of a humanities textbook exceeds $107.00?
II. Can we be reasonably sure that the average price of a textbook is higher at the university bookstore than at Amazon.com, without regard to whether it is a humanities or a hard science textbook? (i.e., combining humanities and hard sciences textbooks together)
| Book ID |
Bookstore Price |
Amazon Price |
Type |
| 1 |
$77.20 |
$80.00 |
2 |
| 2 |
$77.30 |
$77.20 |
1 |
| 3 |
$126.00 |
$124.40 |
2 |
| 4 |
$88.40 |
$88.10 |
1 |
| 5 |
$74.70 |
$76.10 |
1 |
| 6 |
$111.60 |
$110.80 |
1 |
| 7 |
$115.80 |
$115.20 |
1 |
| 8 |
$131.80 |
$126.90 |
2 |
| 9 |
$97.70 |
$96.70 |
2 |
| 10 |
$92.90 |
$95.10 |
2 |
| 11 |
$116.30 |
$116.90 |
1 |
| 12 |
$126.40 |
$123.90 |
2 |
| 13 |
$111.00 |
$112.00 |
1 |
| 14 |
$102.60 |
$102.90 |
2 |
| 15 |
$122.00 |
$120.80 |
2 |
| 16 |
$98.50 |
$99.20 |
2 |
| 17 |
$96.30 |
$95.40 |
2 |
| 18 |
$111.30 |
$109.90 |
2 |
| 19 |
$117.10 |
$115.70 |
2 |
| 20 |
$113.80 |
$112.20 |
1 |
| 21 |
$104.10 |
$101.40 |
2 |
| 22 |
$101.00 |
$100.20 |
2 |
| 23 |
$95.00 |
$93.40 |
2 |
| 24 |
$113.20 |
$112.40 |
1 |
| 25 |
$117.50 |
$117.50 |
2 |
| 26 |
$113.50 |
$111.10 |
1 |
| 27 |
$91.00 |
$89.40 |
1 |
| 28 |
$102.50 |
$102.20 |
2 |
| 29 |
$102.60 |
$102.80 |
2 |
| 30 |
$98.10 |
$100.20 |
1 |
| 31 |
$98.40 |
$94.70 |
2 |
| 32 |
$104.10 |
$102.60 |
1 |
| 33 |
$115.70 |
$116.60 |
2 |
| 34 |
$100.90 |
$100.90 |
1 |
| 35 |
$111.30 |
$110.50 |
1 |
| 36 |
$96.10 |
$93.60 |
1 |
| 37 |
$92.00 |
$92.80 |
1 |
| 38 |
$108.10 |
$107.20 |
2 |
| 39 |
$97.30 |
$99.40 |
1 |
| 40 |
$102.00 |
$102.10 |
2 |
| 41 |
$99.90 |
$98.30 |
1 |
| 42 |
$107.00 |
$107.50 |
2 |
| 43 |
$109.00 |
$108.00 |
1 |
| 44 |
$97.90 |
$98.30 |
2 |
| 45 |
$99.30 |
$98.40 |
2 |
| 46 |
$99.20 |
$99.60 |
2 |
| 47 |
$106.80 |
$106.10 |
1 |
| 48 |
$104.20 |
$106.70 |
2 |
| 49 |
$109.00 |
$108.60 |
2 |
| 50 |
$108.80 |
$109.80 |
2 |
| 51 |
$97.60 |
$100.00 |
1 |
| 52 |
$94.90 |
$95.00 |
1 |
| 53 |
$98.10 |
$98.20 |
1 |
| 54 |
$109.40 |
$109.10 |
2 |
| 55 |
$96.40 |
$96.40 |
1 |
| 56 |
$105.90 |
$104.50 |
1 |
| 57 |
$104.10 |
$104.00 |
1 |
| 58 |
$112.90 |
$109.70 |
2 |
| 59 |
$101.50 |
$102.30 |
2 |
| 60 |
$101.00 |
$99.80 |
1 |
| 61 |
$100.40 |
$99.90 |
1 |
| 62 |
$98.70 |
$99.00 |
1 |
| 63 |
$96.40 |
$96.80 |
1 |
| 64 |
$108.10 |
$107.70 |
2 |
| 65 |
$103.50 |
$106.30 |
2 |
| 66 |
$106.50 |
$106.20 |
2 |