Question

A doctor is measuring the mean systolic blood pressure of female students at a large college. Systolic blood pressure is known to have a skewed distribution. The doctor collects systolic blood pressure measurements from random sample of 28 female students. The resulting 90% confidence interval is (100.4, 159.6). Units of systolic blood pressure are mmHg.Which one of the following conclusions is valid?

a. 90% of the female students at the college have a systolic blood pressure between 100.4 mmHg and 159.6 mmHg.
b. The sampling distribution of means will probably not follow a normal distribution, so we cannot draw a conclusion.
c. We are 90% confident that the mean systolic blood pressure for female students at the college is between 100.4 mmHg and 159.6 mmHg.

Answer 1

c. We are 90% confident that the mean systolic blood pressure for female students at the college is between 100.4 mmHg and 159.6 mmHg.

Explanation:

x% confidence interval for the sample mean being between a and b.

Interpreation:

We are x% sure that the true population mean is between a and b.

The doctor collects systolic blood pressure measurements from random sample of 28 female students. The resulting 90% confidence interval is (100.4, 159.6).

So

We are 90% sure that the mean of all female students at the college is between these two values.

So the correct answer is:

c. We are 90% confident that the mean systolic blood pressure for female students at the college is between 100.4 mmHg and 159.6 mmHg.