40
(Choose 1 answer)
(See picture)
A. 643
B. 639
C. 658
D. 683
A researcher did a pilot sample of 50 individuals and found sample proportion to be 0.20. How many individuals must he survey to develop a 95% confidence interval that has a 0.03 margin of error?
Let z_0.025 1.96; z_0.05-1.645.
