7C.6
Hannah claims that people who live in southern states spend 9 hours more per week outside than do people in northern states. She selects a random sample from each group. The mean number of hours per week that people in southern states spent outside is 18.6, and the mean number of hours per week that people in northern states spent outside is 14.4. A 99 percent confidence interval to estimate the difference in population means (southern minus northern) is (0.4, 8.0) .
Which of the following statements about Hannah’s claim is supported by the interval?

A) Hannah is likely to be incorrect because the difference in the sample means was 18.6 − 14.4 = 4.2 hours.

B) Hannah is likely to be incorrect because 9 is not contained in the interval.

C) The probability that Hannah is correct is 0.99 because 9 is not contained in the interval.

D) The probability that Hannah is correct is 0.01 because 9 is not contained in the interval.

E) Hannah is likely to be correct because the difference in the sample means (18.6 − 14.4 = 4.2) is contained in the interval.