If the width of a confidence interval for $\mu$ is too wide when the population standard deviation $\sigma$ is known, which one of the following is the best action to reduce the interval width?
A) Increase the confidence level
B) Reduce the population standard deviation $\sigma$
C) Increase the population mean $\mu$
D) Increase the sample size n
E) None of the above answers are correct.

Question

Quizplus · Accepted Answer

Increasing the sample size $n$ reduces the width of the confidence interval without altering the population parameters or the confidence level. This is because the standard error of the mean decreases as the sample size increases, leading to a narrower confidence interval.

If the Width of a Confidence Interval For μ\muμ Is Too Wide When the Population Standard Deviation

If the Width of a Confidence Interval For $\mu$ Is Too Wide When the Population Standard Deviation