Ron Marks9 visited five supermarket chains in New York and New Jersey and compared store- and namebrand prices for 30 items listed below.

a. Use the sign test to determine whether or not storebrand items cost less than their name-brand counterparts using α =.01.
b. Use the Wilcoxon signed-rank test to determine if store-brand items cost less than their name-brand counterparts using α = .01.
c. Use the paired-t test to determine if the average cost of store-brand items is less than the average cost of their name-brand counterparts using α = .01.
d. Are the conclusions the same for all three tests? Would you expect them to be? Why or why not?

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Name Brand (S) Store Brand (S) Product Difference (S) Aluminum foil Baked beans Bread crumbs Butter quarters Canned orange segments 207 Canola oil Chocolate-flavored syrup 4.13 Cotton swabs Cranberry juice cockail 2.82 Cream cheese Creamy peanut butter Crescent rolls Dry pasta Dry-roasted peanuts Granulated sugar Grape jelly Ground black pepper Half& Half (quart) Pancake mix Pancake syrup Pretzel twists Quick rice Raisin bran cereal Salad dressing Shredded mozzarella Sour cream Spicy brown mustard Steak sauce Sugar substitute Zippered sandwich bags 2.55 1.22 0.85 4.28 3.22 2.05 2.85 2.71 2.42 1.35 2.05 0.70 0.73 0.74 2.79 2.65 2.47 2.04 3.24 2.84 2.57 2.25 2.91 2.55 3.65 2.55 3.29 1.50 2.02 2.33 2.77 2.70 2.11 0.59