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One Proportion Z Test p is an unknown proportion with some “success” as an outcome. statistic: a number that can be computed from sample data. p̂ (p-hat) is the sample proportion, an estimate of p, the true proportion. # of successful outcomes in sample p̂ # of observations in sample Conditions for Inference on a Single Proportion: •The data are an SRS from the population of interest. •The population is at least 10 times as large as the sample. •For a test of H0 : p __, the sample size n must be so large that both np and n(1 p) are 10 or more. •For a confidence interval, n is so large that both the count of successes np̂ and the count of failures n(1 p̂) are 10 or more. If these conditions are met, a 1 proportion z test (interval) is justified. Draw an SRS of size n from a large population with an unknown proportion of successes, p. An approximate level C confidence interval for p is: p̂ z * p̂(1 p̂) n standard error (SE) To test the hypothesis H0 : p __, compute the z statistic z p̂ p p(1 p) n 1-Proportion Z-interval on calculator STAT TEST A (1-PropZInt…) 1-Proportion Z Test on calculator STAT TEST 5 (1-PropZTest…) PAGE 690 EXAMPLE 12.5 PAGE 691 EXAMPLE 12.6