If a correlated-groups t test and an independent-groups t test both have df = 16, which experiment used more subjects?
A) Both used the same number of subjects (N = 18).
B) Both used the same number of subjects (N = 17).
C) The correlated-groups t test (N = 17) used more subjects.
D) The independent-groups t test (N = 18) used more subjects.

Question

Quizplus · Accepted Answer

An independent-groups t test with df = 16 implies 18 subjects (9 per group), while a correlated-groups t test with df = 16 implies 17 subjects (since df = N - 1 for correlated groups).

If a Correlated-Groups T Test and an Independent-Groups T Test