Question

A national survey of U.S. consumers conducted by the Wall Street Journal asked the question: "In general, how would you rate the service that American businesses provide?" The distribution of responses to this question was as follows:

• Excellent 8%
• Pretty good 47%
• Only fair 34%
• Poor 11%

Suppose a store manager wants to find out whether the results of this consumer survey apply to customers of supermarkets in his city. To do so, he interviews 207 randomly selected customers as they leave the supermarkets in various parts of the city as to their rating of service. Following is the number of responses and distribution of this survey:

• Excellent 21
• Pretty good 109
• Only fair 62
• Poor 15

Please answer the following:

1. Determine whether the observed frequencies of responses from this survey are the same as the frequencies that would be expected on the basis of the national survey. Hint: Think Chi-squared goodness-of-fit, and see Ppts and Selected Example Solutions.
2. Can you describe a Chi-squared application, either goodness-of-fit or test-for-independence, in your profession?

Answer 1

Solution: