I have two groups of 10 participants who were assessed three times during an experiment. To test for differences between groups and across the three assessments, I ran a 2x3 mixed design ANOVA with
group (control, experimental),
time (first, second, three), and
group x time.
group resulted significant, besides there was a significant interaction
group x time.
I don't know very well how to proceed to further check for the differences between the three times of assessments, also respect to group membership. In fact, at the beginning I only specified in the options of the ANOVA to compare all the main effects, using the Bonferroni's correction. However, then I realized that this way they were compared the differences in time of the total sample, without group distinction, am I right?
Therefore, I searched a lot on the internet to find a possible solution, but with scarce results. I only found 2 cases similar to mine, but their solutions are opposite!
- In an article, after the mixed design, the authors ran 2 repeated measures ANOVA as a post-hoc, one for each group of subjects. This way, the two groups are analysed separately without any correction, am I right?
- In a guide on the internet, they say to add manually in the SPSS syntax
COMPARE(time) ADJ(BONFERRONI), just after
/EMMEANS=TABLES(newgroup*time), while running the mixed ANOVA. This way, the three times are compared separately for each group, with Bonferroni correction, am I right?
What do you think? Which would be the correct way to proceed?