A researcher is interested in determining the average number of years employees of a company stay with the company. If past information shows a standard deviation of 7 months, what size sample should be taken so that at 95% confidence the margin of error will be 2 months or less?"
Given sigma=7, z=1.96 (for a 95% confidence) and the margin of error E<=2. By a formula for the margin of ...
This solution determines the sample size that should be taken depending on a 95% confidence and a margin of error.