Confidence Intervals

Question

Assume that a sample is used to estimate a population proportion p. Find the 95% confidence interval for a sample of size 131 with 44% successes. Enter your answer as a tri-linear inequality using decimals (not percents) accurate to three decimal places.

Answer 1

sample proportion phat = 0.44

z-critical value for 95% CI is 1.96

CI for proportion = phat +/- z-critical value * square root ( phat * (1-phat)/sample size)