Refer to the data shown in Question 33.

(a) Compute the value of  and the -value for the test of the null hypothesis of independence.

(b) Summarize the results of this test for the retailer’s sales manager.

Question 33

The following contingency table breaks down a month of customer complaints received by a retailer. Some of those complaining are long-term customers, whereas the rest are recent. There are four types of complaints.

(a) What would it mean to the retailer if customer status and complaint type were dependent?

(b) If many of these complaints come from the same irate customer, do the assumptions needed for a chi-squared test hold?

(c) Does it appear from a brief inspection that customer status and the type of complaint are independent or dependent? Don’t calculate ; just skim the table.

(d) If every count in the table increased by a factor of 2, how would the value of  change (for example, if the first cell were to hold 84 rather than 42)? As in b, think rather than calculate.