sample size

# sample size - Sample Size Determination Simple random...

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Sample Size Determination Simple random sampling is generally used to estimate population parameters such as means, proportions, and variances. When using x to estimate a population mean, for example, one also needs to know how close the estimate is to the true population mean. The error due to sampling variability is given by the standard error of the mean, which is used to construct a confidence interval on the true population mean. The amount of error is determined by the sample size and is a crucial issue in sampling. First, consider the sample size when using x to provide a point estimate of the population mean for variables data. A 100(1 - ) percent confidence interval on x is given by Thus, a 1 - probability exists that the value of the sample mean will provide a sampling error of z /2 / n or less. This sampling error is denoted by E. Solving the equation This sample size will provide a point estimate having a sampling error of E or less at a confidence level of 100(1 - ) percent. To use this formula, specify the confidence level (from which z

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sample size - Sample Size Determination Simple random...

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