1

1. A large corporation with 20,000 employees is interested in estimating the proportion of employees that have completed high school. The proportion is believed to be between 0.6 and 0.8.

(a) What size simple random sample should be selected so that the total length of a 95%

confidence interval for the proportion is less than 0.05?

(b) Assume a similar study is done at another company with 1,200 employees. The administrators there also expect that between 60% to 80% of the employees have completed high school. What is the SRS sample size needed so that the total length of a 95% confidence interval for the proportion is less than 0.05?