I have a question on Paired T-tests in statistics, and degrees of freedom. I understand that N-1 is what I need to do. My homework question is confusing though. It asks:

A school psychologist takes a group of students and pairs them up, making 12 pairs. He is performing a paired T-test. The degrees of freedom would be:
11, 12, 22, 23, or none of the above

If there are 12 pairs then N-1 would be 11... but there are 24 students, which would make N-1 equal 23... which is it??

I am almost thinking it is none of the above because the paired t-test would really only be comparing each person of each pair making N-1 = 1 hahaha! SO LOST