Question

A recent study was conducted in which a random sample of men and a random sample of women were surveyed about whether they were fans of a professional football team. The study found that 39 percent of men in the sample were fans and 22 percent of women in the sample were fans. A 99 percent confidence interval for the difference in the proportion of fans of a professional football team between men and women was reported as (0.133,0.207) . Which of the following statements is the best interpretation of the interval?

a. The difference in the percents of fans of a professional football team between men and women is 17%.
b. There is a 99% chance of finding a difference between 13.3% and 20.7% for the percents of men and women who are fans of a professional football team.
c. We are 99% confident that the percent of men who are fans of a professional football team exceeds that of women by at least 20.7%.
d. We are 99% confident that the difference in the sample percents of men and women who are fans of a professional football team is between 13.3% and 20.7%.
e. We are 99% confident that the difference in the population percents of all men and women who are fans of a professional football team is between 13.3% and 20.7%.

Answer 1

e. We are 99% confident that the difference in the population percents of all men and women who are fans of a professional football team is between 13.3% and 20.7%.

Explanation:

x% confidence interval:

A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.

In this question:

99% confidence interval for the difference in the proportion of fans of a professional football team between men and women is of (0.133, 0.207)

The interpretation is that we are 99% sure that the true proportion is in this interval for the entire population, so the correct answer is given by option e.