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Unformatted text preview: probabilities under the binomial distribution. Slide 27 Interval Estimation of a Population Proportion s Statistic and sampling distribution • the statistic used when making inference about π is: x p= where n x − the number of successes. n − sample size. – Under certain conditions, [n ≥ 30, nπ > 5 and n(1-π ) p is approximately normally distributed, with µ = π and σ 2 = π (1 - π )/n. Slide 28 Interval Estimation of a Population Proportion s Interval estimator for π (1­α confidence level) p ± zα / 2 p (1 − p) / n provided n ≥ 30, np > 5 and n(1 − p ) > 5 Slide 29 Interval Estimation of a Population Proportion s Nielsen Ratings • In a survey of 2000 TV viewers at 11.40 p.m. on a certain night, 226 indicated they watched “The Tonight Show”. • Estimate the number of TVs tuned to the Tonight Show in a typical night, if there are 100 million potential television sets. Use a 95% confidence level. • Solution: We first estimate the proportion, then multiply it by...
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This note was uploaded on 01/17/2010 for the course STATS 2225 taught by Professor Li during the Spring '09 term at Langara.

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