In a public opinion poll 500 people are randomly sample from

In a public opinion poll 500 people are randomly sample from a population, and 268 of them favor Proposition A. Find a 95% confidence interval for the population proportion pi of people who favor the proposition. What sample size would be necessary to obtain a CI with margin of error 0.03?

Solution

2. Here\' how to solve the problem:

ME = .03

n =500

x = 268

p = .536

Z= 1.96

Sample size, n = Z^2 (p)(1-p)/e^2 = (1.96^2)*.536*.464 / .03^2

= 1061.579 or 1062