Repeated measures ANOVA with 2 variables with different levels

MM
2022 4 6
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更新时间：2022 4 7
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Hi, I am trying to run a 2 way RMANOVA on this data called RMANOVA_Table_Analysis. I have also attached this dataset.
I am trying to get the main effect of background, color and the interaction between them. This is what I tried, looks like I am making an error in creating the repeated measures model.
Any pointers on how to do this correctly, would be much appreciated!

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Scott MacKenzie
Scott MacKenzie 2022-4-7

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Change
rm = fitrm(dv, 'uniR - texB ~ 1 ', 'WithinDesign', withinDesign);
to
rm = fitrm(dv, 'uniR-texB ~ 1 ', 'WithinDesign', withinDesign);
Apparently, the fitrm function doesn't like the spaces on each side of the dash.

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MM
MM 2022-4-7
Thank you, Scott!! Removing the space made it work. Rookie mistake.
Another question:
This is the code I use to create the ANOVA table.
[file,path] = uigetfile('*.xlsx');
Q = readtable(file);
dv = array2table(reshape(RMANOVA_Table_Analysis.mean_final_offset, num_subj, []));
% codes for column names: uni = uniform, tex = textured, R=red, G=green B=blue
dv.Properties.VariableNames = {'uniR','uniG','uniB', 'texR', 'texG', 'texB'};
% create the within-subjects design
withinDesign = table([1 1 1 2 2 2]',[1 2 3 1 2 3]','VariableNames',{'Background','Color'});
withinDesign.Background = categorical(withinDesign.Background);
withinDesign.Color = categorical(withinDesign.Color);
% create repeated measures model
rm = fitrm(dv, 'uniR-texB ~ 1 ', 'WithinDesign', withinDesign);
% perform anova (remove semicolon to view table generated by ranova)
AT = ranova(rm, 'WithinModel', 'Background*Color');
If I replace
rm = fitrm(dv, 'uniR-texB ~ 1 ', 'WithinDesign', withinDesign);
with
rm = fitrm(dv, 'uniR-texB ~ Background*Color+Background+Color ', 'WithinDesign', withinDesign)
I'd think I would get a similar response. But instead I get an error instead (below):
rm = fitrm(dv, 'uniR-texB ~ Background*Color+Background+Color ', 'WithinDesign', withinDesign)
Error using classreg.regr.FormulaProcessor (line 385)
The model formula contains names not recognized as predictor or response names.
Error in classreg.regr.MultivariateLinearFormula (line 47)
f = f@classreg.regr.FormulaProcessor(varargin{:});
Error in RepeatedMeasuresModel.fit (line 1312)
formula = classreg.regr.MultivariateLinearFormula(model,varNames);
Error in fitrm (line 77)
s = RepeatedMeasuresModel.fit(ds,model,varargin{:});
Would you know why this is the case?
Scott MacKenzie
Scott MacKenzie 2022-4-7
编辑：Scott MacKenzie 2022-4-7
@MM, you're welcome. In specifying the modelspec for fitrm, the between-subjects variables are placed on the right-hand side of the tilde symbol. Your design does not have any between-subjects variables, so "1" is used on the right-hand side of tilde in the modelspec. In your modified code, you are trying to position the within-subjects variables (Background, Color) as between-subjects variables. That's the reason for the error.
In your original code (with the correction I noted), you will get three effects: the main effects for Background and Color and the Background x Color interaction effect. From your question, I think that's your main objective, right? So I'm not sure what you are trying to do in the second version of fitrm.
BTW, the effect of Color on mean_final_offset was statistically significant, F(2,22) = 4.006, p = .0328. The other two effects were not statistically significant.
MM
MM 2022-4-7
Thank you for explaining! Makes sense why I get the error.

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