Question: When the world's largest retailer, Walmart, decided to enter the grocery marketplace in a big way with its Super Stores, it changed the retail grocery landscape significantly. The other major chains such as Albertsons have struggled to stay competitive. In addition, regional discounters such as WinCo in the western United States have made it difficult for the traditional grocery chains. Recently, a study was conducted in which a "market basket" of products was selected at random from those items offered in three stores in Boise, Idaho: Walmart, WinCo, and Albertsons. At issue was whether the mean prices at the three stores are equal or whether there is a difference in prices. The sample data are in the data file called Food Price Comparisons. Using an alpha level equal to 0.05, test to determine whether the three stores have equal population mean prices. If you conclude that there are differences in the mean prices, perform the appropriate posttest to determine which stores have different means.