The width of a confidence interval around a sample mean depends on which of the following?
A) The sample size
B) The population variance
C) The level of confidence
D) All of the above

Question

Quizplus · Accepted Answer

The width of a confidence interval around a sample mean depends on all three factors – sample size, population variance, and level of confidence. A larger sample size will result in a narrower confidence interval, a higher population variance or standard deviation will result in a wider confidence interval, and a higher level of confidence (e.g. 95% instead of 90%) will result in a wider confidence interval. Therefore, all of the above factors affect the width of a confidence interval.

The Width of a Confidence Interval Around a Sample Mean