A research firm needs to estimate, within 3%, the proportion of junior executives leaving manufacturing companies within three years, with a 95% confidence level. Years ago, a study revealed that 21% of junior executives left their company within five years. You want to update this study. First step is to determine how many junior executives should you survey. Which "formula chunk" should you use?

Question 16 options:

Confidence Interval for a Population Proportion

Choosing an Appropriate Sample Size to Estimate the Population Mean

Confidence Interval for a Population Mean - Sigma Known

Confidence Interval for a Population Mean - Sigma Unknown

Choosing an Appropriate Sample Size to Estimate the Population Proportion