When doing a GLM and you get the "not defined because of singularities" error in the anova output, how does one counteract this error from happening?
Some have suggested that it is due to collinearity between covariates or that one of the levels is not present in the dataset (see: interpreting "not defined because of singularities" in lm)
If I wanted to see which "particular treatment" is driving the model and I have 4 levels of treatment:
Treat 3 &
Treat 4, which are recorded in my spreadsheet as: when
Treat 1 is 1 the rest are zero, when
Treat 2 is 1 the rest are zero, etc., what would I have to do?