Solved – How to test for differences between treatment groups over time

anovarepeated measures

I have two datasets and want to know what analyses to perform and how to implement them (GraphPad Prism is preferable, but SPSS could also help).

  • Case 1: I have 3 treatment groups and 5 time-points. At every time-point I have a score from 1 to 10 from the same animal. I want to check the difference between 3 drugs at every time-point (i.e get the p value for the means in 3 treated-groups at every time-point). Should I use two-way Repeated Measures ANOVA for this purpose or just two-way is also fine?

  • Case 2: I have 2 genotypes and 2 (not 3) treatments but also 5 timepoints. How should I analyse this data?

Best Answer

For case 1 it sounds like a 3 by 5 mixed ANOVA would be suited. You could then perform follow up tests such as analysis of simple effects, post hoc tests, contrasts, etc. depending on the status of initial tests. This scenario is a simple variant of another questions involving a 2 by 5 mixed design. See my detailed answer to that question here for further detail.

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