Question

7. 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. New Drug (n=75) Placebo (n=75) Total Sample (n=150) Mean (SD) Total Serum Cholesterol 182.0 (24.5) 206.3 (21.8) 194.15 (23.2) % Patients with Total Cholesterol < 200 78.0% 65.0% 71.5% a) Generate the 95% confidence interval for the difference in mean total cholesterol levels between treatments b) Generate a 95% confidence interval for the difference in proportions of all patients with total cholesterol < 200. c) How many patients would be required to detect the difference in proportions observed in the current study with a confidence interval of 95%.  

Answer 1

	New Drug (n=75)	Placebo (n=75)	Total Sample (n=150)
Mean (SD) Total Serum Cholesterol	182.0 (24.5)	206.3 (21.8)	194.15 (23.2)
% patients with total cholesterol <200	78.00%	65.00%	71.50%

a)

b)

Here proportion = 71.5% = 0.715

For X nearest value consider it as 0.72 and X = 108

c)