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Unformatted text preview: distribution. • If the population is not normally distributed, but the sample size is sufficiently large, then the sample means will have an approximately normal distribution. Some books define sufficiently large as at least 30 and others as at least 31. The formula for a z-score when working with the sample means is: Finite Population Correction Factor If the sample size is more than 5% of the population size and the sampling is done without replacement, then a correction needs to be made to the standard error of the means. In the following, N is the population size and n is the sample size. The adjustment is to multiply the standard error by the square root of the quotient of the difference between the population and sample sizes and one less than the population size. For the most part, we will be ignoring this in class....
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This document was uploaded on 04/03/2012.
- Spring '09