Question

Each of three supermarket chains in the Denver area claims to have the lowest overall prices. As part of an investigative study on supermarket advertising, a local television station conducted a study by randomly selecting nine grocery items. Then, on the same day, an intern was sent to each of the three stores to purchase the nine items. From the receipts, the following data were recorded. At the 0.025 significance level, is there a difference in the mean price for the nine items between the three supermarkets?

Item	Super's			Ralph's			Lowblaw's
1	$	1.32		$	1.87		$	1.25
2		1.07			1.07			2.22
3		2.46			2.46			5.05
4		2.46			2.46			2.40
5		1.14			1.14			4.15
6		1.23			1.23			4.36
7		1.37			1.37			1.80
8		1.10			1.10			3.08
9		1.29			1.29			4.36

1. State the null hypothesis and the alternate hypothesis.

For Treatment (Stores): Null hypothesis

1. H₀: μ₁ ≠ μ₂ ≠ μ₃

2. H₀: μ₁ = μ₂ = μ₃

• a

• b

2. Alternate hypothesis

• H₁: There is no difference in the store means.

• H₁: There is a difference in the store means.

3. For blocks (Items):

1. H₀: μ₁ = μ₂ = ... μ₉

2. H₀: μ₁ ≠ μ₂ ≠ ... μ₉

• a

• b

4. Alternate hypothesis

• H₁: There is no difference in the item means.

• H₁: There is a difference in the item means.

Answer 1

For treatments:

H0: μ1 = μ2 = μ3

H1: There is a difference in the store means.

For blocks:

H0: μ1 = μ2 = ... μ9

H1: There is a difference in the item means.