The width of a confidence interval estimate for a proportion will be:
A) narrower for 99% confidence than for 95% confidence
B) wider for a sample size of 100 than for a sample size of 50
C) narrower for 90% confidence than for 95% confidence
D) narrower when the sample proportion if 0.50 than when the sample proportion is 0.20
E) none of these

Question

Quizplus · Accepted Answer

The width of a confidence interval is narrower for a lower confidence level (90%) compared to a higher confidence level (95%) because a lower confidence level means you are accepting a higher chance of error, thus requiring less range to capture the true parameter.

The Width of a Confidence Interval Estimate for a Proportion