Question

Paired-/Related Samples T-test

Use it to test whether there is a difference between the two conditions(note: conditions must be RELATED-participants provide in each condition).

You are interested in the relationship satisfaction of young adults before and after they go off to college/university, which separates them from their sweetheart. You asked four couples to rate the satisfaction of their relationship (on a scale of 0-50) before leaving for school and then again after a semester. Here are the data:

Pair Before After

1 40 32

2 38 31

3 36 30

4 42 31

1. State the null and alternative hypotheses as well as your criterion:

2 .State your assumptions

3. Calculate difference scores, the sum of difference scores and the sum of difference scores squared:

4. Calculate t

5. Figure out your degrees of freedom and use this to find the critical t value

6. Reject or fail-to-reject the null hypothesis and state your conclusions.

Answer 1

Let difference d =before -after

(1)

(2)

Assumption: Since sample size is very small so it must be assumed that data is normally distributed.

(3)

Following table shows the calculations:

Before	After	d	(d-mean)^2
40	32	8	0
38	31	7	1
36	30	6	4
42	31	11	9
Total		32	14

4-6)