# 5. Estimating Proportions, Ratios, and Subpopulation Means

Published Online: 10 FEB 2012

DOI: 10.1002/9781118162934.ch5

Copyright © 2012 John Wiley & Sons, Inc.

Book Title

## Sampling, Third Edition

Additional Information

#### How to Cite

Thompson, S. K. (2012) Estimating Proportions, Ratios, and Subpopulation Means, in Sampling, Third Edition, John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118162934.ch5

#### Publication History

- Published Online: 10 FEB 2012
- Published Print: 23 FEB 2012

#### Book Series:

#### Book Series Editors:

- Walter A. Shewhart and
- Samuel S. Wilks

#### ISBN Information

Print ISBN: 9780470402313

Online ISBN: 9781118162934

- Summary
- Chapter

### Keywords:

- confidence interval;
- estimation method;
- propositions;
- ratio estimator;
- subpopulation means

### Summary

To estimate a population proportion using simple random sampling, the usual methods associated with estimating a population mean, forming confidence intervals based on the normal approximation and determining sample size could be used. However, several special features are worth noting: (1) the formulas simplify considerably with attribute data; (2) exact confidence intervals are possible; and (3) a sample size sufficient for a desired absolute precision may be chosen without any information on population parameters. In this chapter a section on estimating a ratio is included mainly to distinguish that situation from estimating a proportion. The chapter talks about the estimating proportions, mean, and totals for subpopulations because when the simple random sample is selected from the whole population, the sample size for the subpopulation is a random variable.

#### Controlled Vocabulary Terms

confidence interval; ratio distribution; Ratio estimator