Question

We know that narrower confidence intervals give us a more precise estimate of the true population proportion. Which of the following could we do to produce higher precision in our estimates of the population proportion?

A. We can select a lower confidence level and increase the sample size.
B. We can select a higher confidence level and decrease the sample size.
C. We can select a higher confidence level and increase the sample size.
D. We can select a lower confidence level and decrease the sample size.

Answer 1

A. We can select a lower confidence level and increase the sample size.

Explanation:

The length of a confidence interval is:

Direct proportional to the confidence interval. This means that the higher the confidence level, the higher the length of the interval is.

Inverse proportional to the size of the sample.This means that the higher the size of the sample, the lower, or narrower, the length of the interval is.

Which of the following could we do to produce higher precision in our estimates of the population proportion?

We want a narrower interval. So the correct answer is:

A. We can select a lower confidence level and increase the sample size.