In the Journal of Marketing Research (November 1996), Gupta studied the extent t
ID: 3153774 • Letter: I
Question
In the Journal of Marketing Research (November 1996), Gupta studied the extent to which the purchase behavior of scanner panels is representative of overall brand preferences. A scanner panel is a sample of households whose purchase data are recorded when a magnetic identification card is presented at a store checkout. The table below gives peanut butter purchase data collected by the A. C. Nielson Company using a panel of 2,500 households in Sioux Falls, South Dakota. The data were collected over 102 weeks. The table also gives the market shares obtained by recording all peanut butter purchases at the same stores during the same period.
Test to determine whether the purchase behavior of the panel of 2,500 households is consistent with the purchase behavior of the population of all peanut butter purchasers. Assume here that purchase decisions by panel members are reasonably independent, and set = .05. (Round your answers 2to 2 decimal places and 2.05 to 3 decimal places.)
Brand Size Number of Purchasesby Household Panel Market
Shares Jif 18 oz. 3,190 19.82% Jif 28 1,874 9.96 Jif 40 744 4.10 Peter Pan 10 4,098 17.80 Skippy 18 6,267 25.66 Skippy 28 1,644 12.98 Skippy 40 1,454 9.68 Total 19,271
Explanation / Answer
Answers:
Part a)
For this chi square test, we all expected values 5
Part b)
2 = 975.59
20.05 = 12.592
Interpretation:
Reject the null hypothesis H0 as the test statistic value is greater than the critical value.
Conclusion: Purchase behaviour is not consistent.