In a study using 8 samples, and in which the population variance is unknown, the distribution that should be used to calculate confidence intervals is
A) a t distribution with 9 degrees of freedom.
B) a t distribution with 7 degrees of freedom.
C) a standard normal distribution.
D) a t distribution with 8 degrees of freedom.

Question

Quizplus · Accepted Answer

When the population variance is unknown and the sample size is small (less than 30), a t distribution should be used to calculate confidence intervals. The degrees of freedom (df) for a t distribution are calculated as the sample size minus one. Therefore, for 8 samples, the degrees of freedom would be 8 - 1 = 7.

In a Study Using 8 Samples, and in Which the Population