Consider again the problem of estimating the mean age, , of all people in the civilian labor

Question:

Consider again the problem of estimating the mean age, μ, of all people in the civilian labor force.
In Example 8.7 on page 322, we found that a sample size of 2250 is required to have a margin of error of 0.5 year and a 95% confidence level. Suppose that, due to financial constraints, the largest sample size possible is 900. Determine the greatest confidence level, given that the margin of error is to be kept at 0.5 year. Recall that σ = 12.1 years.
Extending the Concepts and Skills