In developing a confidence interval estimate for the population mean, the t-distribution is used to obtain the critical value when:
A) the sample contains some extreme values that skew the results.
B) the population standard deviation is unknown.
C) the sampling that is being used is not a statistical sample.
D) the confidence level is low.

Question

Quizplus · Accepted Answer

The t-distribution is used instead of the z-distribution to obtain the critical value when the population standard deviation is unknown, and the sample standard deviation is used as an estimate.

In Developing a Confidence Interval Estimate for the Population Mean