When calculating a confidence interval, the reason for using the t-distribution rather than the normal distribution for the critical value is that the population standard deviation is unknown.

Question

Quizplus · Accepted Answer

The t-distribution is used instead of the normal distribution when the population standard deviation is unknown because it accounts for the additional uncertainty introduced by estimating the standard deviation from the sample.

When Calculating a Confidence Interval, the Reason for Using the T-Distribution