Here are my experimental factors:
- within-factor (two levels): time1, time2.
- between factor (four levels): 4 groups.
I want to test specific post-hoc contrasts comparing:
- group1: time1 vs. time2
- group2: time1 vs. time2
- group3: time1 vs. time2
- group4: time1 vs. time2
to determine if and which group the time factor affects.
SPSS only provides an overall within effect for time averaging 4 groups. Moreover, SPSS only provides post-hoc contrasts for the between groups averaging time
How can I do my specific contrasts?