he case in our study) and this averaged data are normally distributed, then it is not a problem. There is a minority (who are actually correct) that argue you should use non-parametric methods or more complicated tests such as ordinal regression for this type of data. Whichever route you choose, you should understand the data you have and you should be able to justify your decision.</p>
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<li><p>To test assumption 3, extract the residuals from the model (<code>mod_factorial$lm$residuals</code>), create a