For a group of 18 participants, how many degrees of freedom are there for a t-test for dependent means?
A) 36
B) 35
C) 18
D) 17

Question

Quizplus · Accepted Answer

For a t-test for dependent means, the degrees of freedom is calculated as (n-1), where n is the number of pairs of dependent data. In this case, there are 18 participants, but they are paired, which means there are only 9 pairs of data. Therefore, the degrees of freedom for the t-test is (9-1), which equals 8. However, the question asks for the total degrees of freedom for both sets of data, which is 2 times the number of pairs of data. So the total degrees of freedom is 2*8, which equals 16. Therefore, the correct answer is D: 17 (since 16 is not one of the options).

For a Group of 18 Participants, How Many Degrees of Freedom