A study tests the difference between 20 Democrats and 20 Republicans. In this example, the degrees of freedom is equal to ______.
A) 18
B) 19
C) 38
D) 39

Question

Quizplus · Accepted Answer

The degrees of freedom (df) in a two-sample t-test is calculated as follows:

df = n1 + n2 - 2

where n1 is the sample size of Group 1 (Democrats) and n2 is the sample size of Group 2 (Republicans).

In this case, n1 = 20 and n2 = 20, so:

df = 20 + 20 - 2 = 38

Therefore, the correct answer is C (38).

A Study Tests the Difference Between 20 Democrats and 20