TABLE 12-13
According to an article in Marketing News, fewer checks are being written at grocery store checkout stands than in the past. To determine whether there is a difference in the proportion of shoppers who pay by check among three consecutive years at a 0.05 level of significance, the results of a survey of 500 shoppers in three consecutive years are obtained and presented below.

-Referring to Table 12-13, what is the correct conclusion?
A) There is enough evidence that the proportions are all different in the 3 years.
B) There is not enough evidence that the proportions are all different in the 3 years.
C) There is enough evidence that at least two of the proportions are not equal.
D) There is not enough evidence that at least two of the proportions are not equal.

Question

TABLE 12-13
According to an article in Marketing News, fewer checks are being written at grocery store checkout stands than in the past. To determine whether there is a difference in the proportion of shoppers who pay by check among three consecutive years at a 0.05 level of significance, the results of a survey of 500 shoppers in three consecutive years are obtained and presented below.
 
-Referring to Table 12-13, what is the correct conclusion?
A) There is enough evidence that the proportions are all different in the 3 years. 
B) There is not enough evidence that the proportions are all different in the 3 years. 
C) There is enough evidence that at least two of the proportions are not equal. 
D) There is not enough evidence that at least two of the proportions are not equal.

Quizplus · Accepted Answer

A chi-square test for independence can be used to determine if there is a significant difference in the proportion of shoppers paying by check among the three consecutive years. The calculated chi-square value is 18.79 with 4 degrees of freedom and a p-value of 0.0009. This indicates that there is enough evidence to reject the null hypothesis that all three proportions are equal and conclude that at least two of the proportions are not equal. Therefore, the correct conclusion is C: There is enough evidence that at least two of the proportions are not equal.

TABLE 12-13 According to an Article in Marketing News, Fewer Checks Are