# How to preform Anova + Tukey for within-subject design

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Itay Coifman on 8 Feb 2022
Edited: Scott MacKenzie on 9 Feb 2022
Hey all, I am trying to write a code to analyze my experiment results:
My experiment is a within-subject design,each subject (1-5) has done the test at 8 different levels (NL_0,NL_1,TH_450...SH_1350).
The "df.csv" attached describe my results, after transforming the data for within-subject analysis I got "testDf.csv" (might not be needed at all...).
First I want to perform an ANOVA test, and afterward, I want to perform a Tukey test to compare all the levels combinations.
If it was a between-subject design i would use:
df = 40×3 table
subject trialName y _______ ___________ ______ 1 {'NL_0' } 13.3 1 {'NL_1' } 14.543 1 {'SH_1350'} 15.326 1 {'SH_450' } 13.926 1 {'SH_900' } 14.999 1 {'TH_1350'} 14.677 1 {'TH_450' } 14.565 1 {'TH_900' } 14.628 2 {'NL_0' } 13.503 2 {'NL_1' } 13.655 2 {'SH_1350'} 15.159 2 {'SH_450' } 14.014 2 {'SH_900' } 13.967 2 {'TH_1350'} 14.142 2 {'TH_450' } 13.376 2 {'TH_900' } 13.813
[p,tbl,stats] = anova1(df.y,df.trialName)
confidanceLevel = 0.05;
[c,m,h,gnames] = multcompare(stats,'Alpha',confidanceLevel);
After reading some questions at the forum, I figured that I need to use something more like this one:
testDf = 5×9 table
Subject NL_0 NL_1 SH_1350 SH_450 SH_900 TH_1350 TH_450 TH_900 _______ ______ ______ _______ ______ ______ _______ ______ ______ 1 13.3 14.543 15.326 13.926 14.999 14.677 14.565 14.628 2 13.503 13.655 15.159 14.014 13.967 14.142 13.376 13.813 3 16.356 16.029 16.695 16.005 16.727 16.772 16.504 16.805 4 13.98 13.563 15.107 14.232 14.627 14.188 14.381 14.09 5 14.41 14.344 16.66 15.733 16.126 15.602 15.495 15.146
measurements = table([1 2 3 4 5 6 7 8]','VariableNames',{'Measurements'});
rm = fitrm(testDf,"NL_0,NL_1,SH_1350,SH_450,SH_900,TH_1350,TH_450,TH_900~Subject"...
,'WithinDesign',measurements);
ranovatbl = ranova(rm)
tbl = multcompare(rm,'NL_0')
The multicompare doesn't work, and I think I have done something wrong in the process of getting there...
I would really appreciate your help.
Thanks,
Itay

Scott MacKenzie on 9 Feb 2022
Edited: Scott MacKenzie on 9 Feb 2022
I believe the issue is you've incorrectly specified the variable as the second argument in multcompare. Try
tbl = multcompare(rm, 'Measurements')

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