I hope someone can help me interpreting my results.

I ran two tests, each with three participant groups. So I have a within-subject factor with 2 levels and a between-subject factor with 3 levels. Interaction is significant.

I attached a picture to show you the data.

How do I proceed from here? Which group caused the interaction?

From the picture I infer, that the red group caused the interaction. I ran three additional repeated-measures-anova for red-green, red-blue, and green-blue comparisons. These tests verified my guess. But I think this is not a legal statistical procedure. How can I statistically find out which of the three groups caused the interaction?

Is it even possible?

I am thankful for any idea or help.

Have a great day

minimax

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additional information

The x-axis of the picture just shows test 1 and 2. The y-axis shows scores. The lines are the connected performances of the three different groups for test 1 and 2.

In case you can't see the picture: I have three groups: red, green and blue.

red and blue line cross each other, so that red scores higher in test 1 and blue scores higher in test 2. the green line is parallel to the blue one, but on overall lower scores and no crossing with the red line.

First I ran a 2x3 repeated measures anova. Both main effects (groups and tests) were significant. Interaction was significant, too.

Afterwards I ran simple main effects analysis:

For all groups the scores in test 1 and test 2 are significantly different.

For test 2 the scores of the different groups are not significantly different.

For test 1 the scores of the different groups are significantly different.

multiple comparison (bonferroni corrected+) for test 1 showed that the green group scores significantly different from the other two.