1. The following data were collected in a clinical trial to compare a new drug to a placebo for its effectiveness in lowering total serum cholesterol.
Generate a 95% confidence interval for the difference in mean total cholesterol levels between treatments.
New Drug
(n=75) Placebo
(n=75) Total Sample
(n=150)
Mean (SD) Total Serum Cholesterol 185.0 (24.5) 204.3 (21.8) 194.7 (23.2)
% Patients with Total Cholesterol < 200 78.0% 65.0% 71.5%
Upper CI. Lower CI. Based on confidence interval which of the following are true ?
How many patients would be required to ensure 95% confidence interval has a margin not exceeding 5%?