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In: Statistics and Probability

How large a sample should be selected so that the maximum error of estimate for a...

How large a sample should be selected so that the maximum error of estimate for a 95% confidence interval for the population mean is 2.1 Assume the population standard deviation is 10.5.

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Expert Solution

The minimum sample is calculated if the distribution assumed as normal :

Where E= Maximum error and Z =Standard normal score at significance level which is 1.96 for 95% confidence interval calculated using the Z table shown below with illustration.

and =Population standard deviation=10.5

The Z table is:


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