Alpha Geek
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14–56. When new paperback novels are promoted at bookstores, a display is often arranged with copies of the same book with differently colored covers. A publishing house wanted to find out whether there is a dependence between the place where the book is sold and the color of its cover. For one of its latest novels, the publisher sent displays and a supply of copies of the novel to large bookstores in five major cities. The resulting sales of the novel for each city–color combination are as follows. Numbers are in thousands of copies sold over a 3-month period.
Color
|
City New York |
Red 21 |
Blue 27 |
Green 40 |
Yellow 15 |
|
Total 103 |
|
Washington |
14 |
18 |
28 |
8 |
|
68 |
|
Boston |
11 |
13 |
21 |
7 |
|
52 |
|
Chicago |
3 |
33 |
30 |
9 |
|
75 |
|
Los Angeles |
30 |
11 |
34 |
10 |
|
85 |
Total 79 102 153 49 383
a. Assume that the data are random samples for each particular color–city combination and that the inference may apply to all novels. Conduct the overall test for independence of color and location.
b. Before the analysis, the publisher stated a special interest in the issue of whether there is any dependence between the red versus blue preference and the two cities Chicago versus Los Angeles. Conduct the test. Explain.