Interpretation Confidence Interval

The U.S. Food and Drug Administration (FDA) performed a study that compared the carbohydrate content (as a percentage of weight) of several major brands of corn and potato chips. Fourteen brands of corn chips were sampled and 14 brands of potato chips were sampled. Datawas collected and the following 95% confidence intervalwas computed for the difference in means. Intrepret the 95% confidence interval for the difference in the meancarbohydrate content between the Corn Chip and Potato Chip groups.

The C.I. is:

where = the average carbohydrate content as a percentage of weight in corn chips.

and = the average carbohydrate content as a percentage of weight in potato chips.

Select the best answer below.

Choose one answer.
A. We are 95% confident that there is no statistically significant difference in the average carbohydrate content as a percentage of weight between corn chips and potato chips.
B. We are 95% confident that the average carbohydrate content as a percentage of weight in corn chips is lower than the average carbohydrate content as a percentage of weight in potato chips.
C. We are 95% confident that the average carbohydrate content as a percentage of weight in corn chips is higher than the average carbohydrate content as a percentage of weight in potato chips.
D. None of these are correct.

Answer:

C. We are 95% confident that the average carbohydrate content as a percentage of weight in corn chips is …

The solution provides the interpretation of the 95% confidence interval for proportions.