Inference for Proportions Chapter 12

Inference for a Population Proportion Section 12.1

Sample Proportion p hat mean = p standard deviation (p(1 – p)/n) # of successes/# of observations mean = p standard deviation (p(1 – p)/n) If np and n(1 – p)  10, p hat is approximately normal

standard error-replace p with p hat Confidence interval z statistic standard error-replace p with p hat Confidence interval estimate ± z* SEestimate

Conditions for Inference About a Proportion Data are an SRS from population on interest Population at least 10 times as large as sample For test H0: p = p0 sample size n so large that both np0 and n(1 – p0) are 10 or more

Formulas for z procedures Formula for samples size for desired margin of error p.695

Practice Problems pg. 698 #12.13-12.19, 12.21