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A researcher is interested in determining the average number of years new teachers remain in the...

A researcher is interested in determining the average number of years new teachers remain in the classroom. If past information shows a standard deviation of 5 years, what size sample should be taken so that at 95% confidence the margin of error will be 6 months or less?

a. 3
b. 385
c. 2
d. 384
Math   Statistics-And-Probability   
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