Question

A random sample of 235 females and 240 males is obtained for a clinical trial. Construct...

A random sample of 235 females and 240 males is obtained for a clinical trial. Construct a 95% confidence interval to estimate the proportion of females in all such samples.

Express your answer to four decimal places.

Homework Answers

Answer #1

Sample proportion of females = 235 / (235 + 240) = 0.495

95% confidence interval for p is

- Z/2 * sqrt [ ( 1 - ) / n) ] < p < + Z/2 * sqrt [ ( 1 - ) / n) ]

0.495 - 1.96 * sqrt( 0.495 * 0.505 / 475) < p < 0.495 + 1.96 * sqrt( 0.495 * 0.505 / 475)

0.4500 < p < 0.5400

95% CI is ( 0.4500 , 0.5400)

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