Question

If you have two samples, one with n1 = 21 and the other with n2 = 14, and you are performing a pooled-variance t test, how many degrees of freedom do you have for this test?

Answer 1

For a pooled-variance t test with two samples with sizes n1 = 21 and n2 = 14, the degrees of freedom is 33, calculated by summing up the sizes of both groups and subtracting 2.

Step-by-step explanation:

When performing a pooled-variance t test with two samples where n1 = 21 and n2 = 14, you calculate the degrees of freedom by adding the sizes of the two samples and subtracting 2. Therefore, the degrees of freedom (df) for this test is:

df = (n1 - 1) + (n2 - 1) = (21 - 1) + (14 - 1) = 20 + 13 = 33.

This is because the pooled-variance t test assumes that the two samples come from populations with the same variance, and each sample contributes to this estimate, hence the formula df = (n1 - 1) + (n2 - 1).