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Unformatted text preview: Business Statistics Fifth Edition Ken Black Chapter 7: Sampling Chapter 7: Sampling and and Sampling Distributions Sampling Distributions These notes are not to be reproduced without the written permission of F.B. Alt 71 7.1 Sampling • Purpose of taking a sample ? ________________________________ • It is usually impossible to measure every unit in the population because: o population is too large, o cost would be prohibitive, o too time consuming, • Instead, we take a sample, or a subset, of the population. • Sampling techniques are either probability based (random sampling) or nonprobability based (nonrandom sampling) [Black, page 221] • Of the probability based sampling techniques, we will only consider simple random sampling [Black, page 222] These notes are not to be reproduced without the written permission of F.B. Alt Population Parameter Sampl Statist Statisti0 parameter i ’ a parameter Select a random sample (size n) f statistics from sample to sampleg selected. L  72 • Simple Random Sample : A sample chosen in such a way so that all samples of size n are equally likely to be selected for the sample. • The sampling frame is the list of units “allegedly” comprising the population. • Choosing a SRS o Assign a numerical code to every member of the population. o Use randomly generated numbers [page 774] to select the n units in the sample. Example : Pick a random sample of size 3 from the 30 stocks in the DJIA Alcoa Inc. Common Stock American Express Company Boeing Company (The) Bank of America Corporation Caterpillar, Inc. Cisco Systems, Inc. Chevron Corporation E.I. du Pont de Nemours Walt Disney Company (The) General Electric Company Home Depot, Inc. HewlettPackard Company International Business Machines Intel Corporation Johnson & Johnson JP Morgan Chase & Co. JP Morgan Chase & Co....
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This note was uploaded on 09/07/2011 for the course BMGT 231 taught by Professor Staff during the Fall '08 term at Maryland.
 Fall '08
 staff
 Business

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