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Unformatted text preview: Sample Proportion: b p = X n where X is number of success in the sample • When n > 30 , by CLT b p ∼ N ( p, pq n ) Estimation • Estimator - a sample statistic that is used to estimate an unknown population parameter. • Estimate - an actual numerical value obtained for an estimator. • For example, if X = 10 , X is an estimator; ‘10’ is an estimate. Point Estimator Criteria of a Good Estimator • No Bias — E ( estimator ) = population parameter — For example, E ¡ X ¢ = µ , so X is an unbiased estimator for µ. • Small Variance — The estimators vary about the true parameter & this variation should be small i.e. standard error of the estimators should be small — V ar ( X ) < V ar ( e X ) where e X is any other estimator of population mean — Therefore, an unbiased estimator with smaller variance is closer to the population parameter than the one with larger variance. 2...
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This note was uploaded on 01/06/2011 for the course ISOM 111 taught by Professor Hu,inchi during the Fall '10 term at HKUST.
- Fall '10