Researchers Are Interested in Investigating the Effect of a Drug

Multiple Choice

Researchers are interested in investigating the effect of a drug that is to be used in the treatment of patients who have glaucoma (an eye disorder associated with high eye pressure) . In a volunteer sample of 35 patients with glaucoma in both eyes, one eye of each patient was randomly assigned to this drug, and the other eye was given a placebo. After one week, the eye pressure was measured on each eye. The difference in eye pressure between the two eyes (drug - placebo) was measured for each patient. The sample mean difference in eye pressure was -1.21 mmHg (millimeters of mercury) , and the sample standard deviation of the differences was 4.67 mmHg.
-Suppose a 95% confidence interval for the population mean difference in eye pressure is (L, U) . How would you interpret this interval?

A) We are 95% confident that each patient's difference in eye pressure (drug - placebo) will be between L and U mmHg.
B) We are 95% confident that the population mean difference in eye pressure (drug - placebo) if treated would be between L and U mmHg.
C) Approximately 95% of patients will have a difference in eye pressure (drug - placebo) between L and U mmHg.
D) In the long run, 95% of samples will produce a confidence interval of L to U mmHg.