Fifteen sets of identical twins are the subjects in a drug experiment. One twin receives the treatment, and the other twin receives a placebo. What are the degrees of freedom for the appropriate t-test?
A) 14
B) 15
C) 28
D) 29
E) 30

Question

Quizplus · Accepted Answer

The degrees of freedom for a paired t-test, which is appropriate in this case since each twin pair acts as a matched pair, is calculated as the number of pairs minus one. Here, there are 15 pairs of twins, so the degrees of freedom are 15 - 1 = 14.

Fifteen Sets of Identical Twins Are the Subjects in a Drug