How to obtain residuals after using 'fitrm'?

Hello,

I have been trying to obtain the residuals after using 'fitrm' with this formula: 'VarLeft-VarRight~Group', so that I can test for normality and outliers, but I haven't found a way of doing this on MATLAB. I was wondering if anybody knows how to do this?

Thanks!

Answer 1

[dpb]

It doesn't seem as they have implemented it directly; you'll have to compute the residuals as the difference between the resulting model prediction and the input data at the desired data points...

There's an example for the Fisher iris data set that doesn't specifically compute the residuals themselves, but calculates the predicted values and plots them in comparison to the input data...just follow its lead...

load fisheriris
t = table(species,meas(:,1),meas(:,2),meas(:,3),meas(:,4), ...
    'VariableNames',{'species','meas1','meas2','meas3','meas4'});
Meas = dataset([1 2 3 4]','VarNames',{'Measurements'});
rm = fitrm(t,'meas1-meas4~species','WithinDesign',Meas);
Yhat=predict(rm,t([1 51 101],:))

Yhat = 3×4

5.0060 3.4280 1.4620 0.2460 5.9360 2.7700 4.2600 1.3260 6.5880 2.9740 5.5520 2.0260

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Y=t([1 51 101],[2:end])

Y = 3x4 table
    meas1    meas2    meas3    meas4
    _____    _____    _____    _____

     5.1      3.5      1.4      0.2 
       7      3.2      4.7      1.4 
     6.3      3.3        6      2.5 

Res=Y-Yhat

Res = 3x4 table
    meas1     meas2    meas3     meas4 
    ______    _____    ______    ______

     0.094    0.072    -0.062    -0.046
     1.064     0.43      0.44     0.074
    -0.288    0.326     0.448     0.474

Use your data a results similarly...