Question

Assume that a sample is used to estimate a population proportion p. Find the 95% confidence interval for a sample of size 395 with 73% successes. Enter your answer as an open-interval (i.e., parentheses) using decimals (not percents) accurate to three decimal places.

C.I. =

Answer 1

95% confidence interval for p is

- Z * sqrt ( ( 1 - ) / n) < p < + Z * sqrt ( ( 1 - ) / n)

0.73 - 1.96 * sqrt( 0.73 * 0.27 / 395) < p < 0.73 + 1.96 * sqrt( 0.73 * 0.27 / 395)

0.690 < p < 0.774

95% Ci is ( 0.690 , 0.774 )