My goal is to compare multiple groups to determine if a certain "variable of interest" is different between different groups (in the example below: blue, red, and orange). Normally, this statistical test could be solved with an ANOVA, but the "variable of interest" is influenced by a co-variate (in the example below this is speed). In this case, an ANCOVA would be the appropriate test, but the data I am working with has two groups that are influenced by speed (blue and red) and one variable that is not influenced by speed (orange). Obviously this violates the assumptions of an ANCOVA, but I am unclear as what to do in order to compare the groups to each other.

I appreciate any advise on this issue. Thank you so much.

-Michael

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