From a population that is normally distributed, a sample of 25 elements is selected and the standard deviation of the sample is computed. For the interval estimation of $\mu$, the proper distribution to use is the
A)normal distribution
B)t distribution with 25 degrees of freedom
C)t distribution with 26 degrees of freedom
D)t distribution with 24 degrees of freedom

Question

Quizplus · Accepted Answer

When estimating the mean $\mu$ of a normally distributed population with a sample size less than 30 and unknown population standard deviation, the t distribution is used with $n-1$ degrees of freedom, where $n$ is the sample size. Here, $n = 25$, so the degrees of freedom is 24.

From a Population That Is Normally Distributed, a Sample of 25