Question

If we doing a paired-sample test with samples of n₁ = 20 and n₂ = 20, the number of degrees of freedom is equal to

		A.39
		B.38
		C.19
		D.18

Answer 1

The paired test provides an hypothesis test of the difference between population means for a pair of random samples whose differences are approximately normally distributed.

Test statistics for paired sample test is -

t = d bar / (s_d /sqrt(n))

where d bar is the mean difference

S_d is the standard deviation of data

n is the sample size

For this test statistics we get degrees of freedom is (n - 1).

We have n = 20

Hence we get degrees of freedom = n - 1 = 19

Hence C) 19 is the correct answer.

Hope this will help you. Thank you :)