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.
-A 98% theory-based confidence interval for the population mean difference in eye pressure is (-3.14, 0.72) mmHg.Does this interval give us evidence that the drug reduces eye pressure in glaucoma patients, on average?

A) Yes, since most of the interval is negative.
B) No, since the sample size is too small.
C) No, since theory-based methods are not valid for this data set.
D) No, since zero is contained in the interval.