Seventy-five (75) people with hypertension were given a new drug for the treatment of their condition. Blood pressure was lowered sufficiently to reduce the risk of serious outcomes in 20 of the 75 patients.
(B) Calculate a 95% confidence interval for the proportion. Show all work, and interpret your findings.
CI95 = p ± 1.96[√(pq/n)]
p = 20/75 = .27
q = 1 - p = 1 - .27 = .73
n = 75
Substitute into the formula to find the confidence interval.