Hi! A new drug is proposed to prevent the development of glaucoma in people with high intraocular

pressure (IOP). A pilot study is conducted with the drug among 10 patients. After 1 month of using

the drug, their mean IOP decreased by 5 mmHg with a standard deviation of 10 mmHg. A larger

study of a the new drug to prevent glaucoma is proposed. We wish to determine the sample size

needed to achieve the effect size observed in the pilot study with a maximum type II error of 10%

and type I error of 5% using an appropriate two-sided test.