In: Statistics and Probability
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.
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)