Exercise 10.40 examined an advertisement for Albertsons, a supermarket chain in the western United States. The advertiser claims that Albertsons has consistently had lower prices than four other full-service supermarkets. As part of a survey conducted by an “independent market basket price-checking company,” the average weekly total based on the prices of approximately 95 items is given for five different supermarket chains recorded during 4 consecutive weeks.

a. What type of design has been used in this experiment?

b. Conduct an analysis of variance for the data.

c. Is there sufficient evidence to indicate that there is a difference in the average weekly totals for the five supermarkets? Use α = .05.

d. Use Tukey’s method for paired comparisons to determine which of the means are significantly different from each other. Use α = .05.