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Calculating the sample size given confidence levels and standard deviation.

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A researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?

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The solution addresses a researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?

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We can simply assume N samples are needed to have the confidence interval of 200 (which is actually two-tailed as ...

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