Warehouse clubs such as Costco, BJ’s, and Sam’s Club compete with traditional supermarkets by advertising lower prices to customers who are willing to pay a membership fee and purchase in bulk quantities. Suppose a consumer group would like to investigate if warehouse clubs have different average prices than traditional supermarkets. Data in the Excel file warehouse. xlsx show the price of 11 grocery items from a supermarket and three warehouse clubs.
a. Choose the most appropriate ANOVA procedure using α = 0.05 to determine if a difference exists in the average price of these items at the four stores?
b. Was blocking effective? Why or why not?
c. If warranted, determine which pairs of stores were different using α = 0.05.
d. Verify your results with Excel.