In an advertisement in a local newspaper, Best Food supermarket attempted to convince consumers that it offered them the lowest total food bill. To do this, Best Food presented the following comparison of the prices of 60 grocery items purchased at three supermarkets-Best Food, Public, and Cash' N Carry-on a single day.

If we use these data to compare the mean prices of grocery items at the three supermarkets, then we have a randomized block design where the treatments are the three supermarkets and the blocks are the 60 grocery items. Below is the MINITAB output of a randomized block ANOVA of the supermarket data.

a. Test the null hypothesis H0 that no differences exist between the mean prices of grocery items at the three supermarkets. Do the three supermarkets differ with respect to mean grocery prices?
b. Make pairwise comparisons of the mean prices of grocery items at the three supermarkets by using Tukey simultaneous 95 percent confidence intervals. Which supermarket has the lowest mean prices?

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Best Food Public Cash N Carry Best Food Public Cash N Carry tem 1.21 Keb Graham Crust 79 Spiffits Glass Prog Lentil Soup Lipton Tea Bags 2.07 Carnation Hot Coco 1.59 Crystal Hot Sauce 70 CIF/N/ Coffee Bag .17 Soup Start Bf 39 Camp Pork & Beans 44 Sunsweet Pit Prune 98 DM Vgcls Grdn Duet 1.07 Argo Corn Starch 69 Sno Drop Bowl Clnr 53 Cadbury Milk Choc 79 Andes Crm/De Ment 1.09 Combat Ant & Roach 2.33 Joan/Arc Kid Bean 45 La Vic Salsa Pican 1.22 Moist N Beef/Chz 2.39 Ortega Taco Shells 1.08 Fresh Step Cat Lit 3.58 Field Trial Dg/Fd 3.49 Tylenol Tablets Rolaids Tablets Plax Rinse Correctol Laxative 3.44 Tch Scnt Potpourri 1.50 Chld Enema 2.250 Gillette Atra Plus 5.00 Colgate Shave 1.29 1.28 2.59 Big Thirst Towel Camp Crm/Broccoli Royal Oak Charcoa 2.99 Combo Chdr/Chz Snk 1.29 Sure Sak Trash Bag 1.29 Dow Handi Wrap 1.59 White Rain Shampoo 96 Post Golden Crisp2.78 Surf Detergent Sacramento TJuice SS Prune Juice V-8 Cocktail Rodd Kosher Dill Bisquick Kraft Italian Drs BC Hamburger Helper 1.46 Comstock Chrry Pie 1.29 Dawn Liquid King 2.59 DelMonte Ketchup 1.05 Silver Floss Kraut Trop Twist Beverag 1.74 Purina Kitten Chow 1.09 Niag Spray Starch Soft Soap Country 97 Northwood Syrup Bumble Bee Tuna Mueller Elbow/Mac 2.09 Kell Nut Honey Crn 2.95 Cutter Spray Lawry Season Salt 2.28 3.59 1.29 1.39 1.79 2.39 2.29 79 1.89 1.99 1.55 1.94 1.39 2.03 2.29 1331.10 1.29 1.28 2.09 1.75 2.58 89 1.29 1.28 1.30 109 2.39 2.79 2.09 1.75 1.69 2.29 59 2.99 .81 2.15 3.79 3.81 3.793.49 5.98 2.20 2.49 2.53 3.59 1.89 2.25 1.05 1.29 5.98 5.29 1.37 1.37 3.98 1.89 2.69 3.25 3.95 2.97 2.69 3.23 3.69 2.85 5.24 .94 Two-way ANOVA: PRICE versus MARKET, ITEM Source DF Market tom Erzor Total Descriptive Statistics: PRICE Variable MARKET PRICE NMean 60 1.665 CASH N CARRY 601.925 60 1.920 MS 1.32063 59 215.595 3.65415 108.54 .000 0.03367 2.641 39.23 0.000 BEST FOoD 118 179 3.973 222.209 PUBLIC