9 1. Estimation and Confidence © 2004 by The McGrawHill Companies, Inc. All rights reserved. 9 2. When you have completed this chapter, you will be able to: Define a point estimator, a point estimate, and desirable. properties of a point estimator such as. unbiasedness, efficiency, and consistency. . Define an interval estimator and an interval estimate Define a confidence interval, confidence level, margin of . error, and a confidence interval estimate Construct a confidence interval for the population mean . when the population standard deviation is knownCopyright © 2004 by The McGrawHill Companies, Inc. All rights reserved. 9 3. Construct a confidence interval for the population variance . when the population is normally distributed Construct a confidence interval for the population mean . when the population is normally distributed and the . population standard deviation is unknown Construct a confidence interval for a population proportion Determine the sample size for attribute and . variable © 2004 by The McGrawHill Companies, Inc. All rights reserved. Terminology. 9 4. Point Estimate is a single value (statistic) used to . estimate a population value (parameter). Interval Estimate states the range within which a . population parameter probably lies. Confidence Interval is a range of values within which . the population parameter . is expected to occurCopyright © 2004 by The McGrawHill Companies, Inc. All rights reserved. Desirable properties of a point estimator. 9 5 •• efficient. efficient. possible values are concentrated . close to the value of the parameter •• consistent. consistent. values are distributed evenly on . both sides of the value of the . parameter. •• unbiased. unbiased. unbiased when the expected value equals the value . of the population parameter being estimated. . Otherwise, it is biased!Copyright © 2004 by The McGrawHill Companies, Inc. All rights reserved. Terminology. 9 6 Standard error of the sample mean . Standard error of
