Q1) Newspaper article explained the opening of Whole Foods Market in Time-Warner building in New York City. Following data compared prices of some kitchen staples at new Whole Foods Market and at Fairy supermarket located about 25 blocks from Time-Warner building:
|
Item
|
Whole Foods (X1)
|
Fairway(X2)
|
|
Half-gallon milk
|
2.19
|
1.35
|
|
Dozen eggs
|
2.39
|
1.69
|
|
Tropicana orange juice (64 oz)
|
2
|
2.49
|
|
Head of Boston lettuce
|
1.98
|
1.29
|
|
Ground round, 1 lb
|
4.99
|
3.39
|
|
Bumble Bee tuna, 6 oz can
|
1.79
|
1.33
|
|
Uranny Smith apples (1 lb)
|
1.69
|
1.49
|
|
Box DeCecco linguini
|
1.99
|
1.59
|
|
Salmon Steak 1 lb
|
7.99
|
5.99
|
|
Whole chicken, per pound
|
2.19
|
1.49
|
i) At 0.01 level of significance, is there evidence that mean price is higher at Whole Foods Market than at Fairyway supermarket?
ii) Interpret the meaning of p-value in (i).
iii) What supposition is essential to carry out the test in (i)?