Problem
A sample has a sample proportion of 0.3 . Which sample size will produce the widest $95 \%$ confidence interval when estimating the population parameter? A. 100 B. 90 C. 75 D. 50
Solution
Step 1 ：Calculate the margin of error for each sample size using the formula: Margin of Error = Z * sqrt((p * (1 - p)) / n), where Z = 1.96, p = 0.3, and n is the sample size.
Step 2 ：Compare the margins of error and choose the sample size with the widest confidence interval. \(\boxed{50}\)
