From a population that is normally distributed with an unknown standard deviation, a sample of 25 elements is selected.For an interval estimation of the population mean, the proper distribution to use is the:
A)t distribution with 24 degrees of freedom
B)t distribution with 26 degrees of freedom
C)normal distribution
D)standard normal distribution
E)none of the above

Question

Quizplus · Accepted Answer

When the population standard deviation is unknown and the sample size is small (n < 30), the t distribution is used for interval estimation of the population mean. The degrees of freedom (df) for the t distribution are calculated as n - 1, where n is the sample size. Here, with a sample size of 25, the degrees of freedom would be 25 - 1 = 24.

From a Population That Is Normally Distributed with an Unknown