Repeated Measures ANOVA - getting very small p-value when there is no difference between conditions

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Prabhjot Dhami
Prabhjot Dhami on 3 Feb 2022
Answered: Dona on 16 May 2022
I am having trouble with conducting a repeated measures ANOVA in matlab. I have one group of 31 participants, who underwent 6 different testing conditions. Please find the data table attached.
% fitting anova
withinDesign = table([1 2 3 4 5 6]','VariableNames',{'SiteOfStimulation'});
withinDesign.SiteOfStimulation = categorical(withinDesign.SiteOfStimulation);
rm = fitrm(t, 'curlpfc_timei,curlmc_timei,curlipl_timei,currpfc_timei,currmc_timei,curripl_timei ~ 1', 'WithinDesign', withinDesign);
ranovatbl = ranova(rm, 'WithinModel','SiteOfStimulation');
tbl = multcompare(rm, 'SiteOfStimulation', 'ComparisonType', 'bonferroni');
Now, there are clearly no differences in the condition by plotting them, as well as looking at the multcompare results. However, when fitting the ranova, I am getting extremely large F-values and small p-values, when I was expecting the opposite.
Any insight into what I am doing wrong would be greatly appreciated.
Thank you.

Answers (1)

Dona on 16 May 2022
I am going through the same issue. Did you find a solution.
Thank you in advance


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