Question

Traditionally, wine has been sold in glass bottles with cork stoppers. The stoppers are supposed to keep air out of the bottle because oxygen is the enemy of the wine. Particularly red wine. Recent research appears to indicate that metal screw caps are more effective in keeping air out of the bottle. However, metal caps are perceived to be inferior and usually associated with cheaper brands of wine. A random sample of 130 people who drink at least one bottle per week on average was asked to participate in an experiment. All were given the same wine in two types of bottles. One group was given a corked bottle, and the other group of people was given a bottle with a metal cap and asked to taste the wine and indicate what they think the retail price of the wine should be.

METAL PRICE = 13 12 16 5 7 8 6 10 11 9 6 16 15 15 9 17 6 10 11 7 8 11 22 21 11 6 11 10 17 12 13 11 16 18 12 11 11

CORK PRICE = 16 10 15 10 17 11 14 13 11 14 11 16 18 16 10 17 14 14 16 7 10 12 19 15 16 14 9 12 21 13 10 16 12 16 13 17 17

QUESTION- The 95% confidence interval is:

Lower Confidence Limit=                          show the formula used to calculate it.

Upper Confidence Limit=                          show the formula used to calculate it

Answer 1

Let denote the mean retail price for metal cap and cork cap respectively.

Lower Confidence Limit = -3.94

Upper Confidence Limit = -0.49