Does it cost more to buy at a warehouse club than to buy store brands? To investigate this, a random sample of 10 purchases was selected, and the prices were compared. The prices for the products are stored in the accompanying data table. Complete parts (a) through (c).

Product

Warehouse club

Store brand

Mustard

3.32

2.60

Disinfectant wipes

1.33

1.89

Vegetable oil

2.48

1.81

Cereal

3.11

1.91

Premium pasta sauce

1.88

4.82

Multivitamins

6.74

5.19

Laundry detergent

13.23

9.14

Disposable diapers

18.33

17.04

Cream cheese

0.93

1.62

Bagged coffee

9.69

13.47

At the 0.100.10

level of significance, is there evidence that the mean price of the warehouse club purchases is greater than the store-brand purchases?

Let mu 11

be the mean prices at the warehouse club and let mu 22

be the mean prices for the store brands. State the null and alternative hypotheses. Choose the correct answer below.

A.

Upper H 0H0:

mu Subscript Upper DDequals=0

left parenthesis where mu Subscript Upper D Baseline equals mu 1 minus mu 2 right parenthesiswhereD=12

Upper H 1H1:

mu Subscript Upper DDnot equals0

B.

Upper H 0H0:

mu Subscript Upper DDnot equals0

left parenthesis where mu Subscript Upper D Baseline equals mu 1 minus mu 2 right parenthesiswhereD=12

Upper H 1H1:

mu Subscript Upper DDequals=0

C.

Upper H 0H0:

mu Subscript Upper DDless than or equals0

left parenthesis where mu Subscript Upper D Baseline equals mu 1 minus mu 2 right parenthesiswhereD=12

Upper H 1H1:

mu Subscript Upper DDgreater than>0

D.

Upper H 0H0:

mu Subscript Upper DDgreater than or equals0

left parenthesis where mu Subscript Upper D Baseline equals mu 1 minus mu 2 right parenthesiswhereD=12

Upper H 1H1:

mu Subscript Upper DDless than<0

What assumption is necessary about the population distribution in order to perform this test?

Review the assumptions required for a paired t test for the mean difference.

Determine the p-value in (a) and interpret its meaning.