When performing GLM (General Linear Model) ANOVA for L9 array experiments an error message "Denominator of F-test is zero or undefined". Also all values in column labeled F are displayed as **. Is there any possible way to overcome this?
Apparently you don't have enough observations (data) to analyze your model. Try excluding some of the factors from the model.
Hi there!
When a model is too complex, for example, it has a lot of variables (even interactions), and the sample is not "big" enough, this kind of situations may happen.
You need to "win" degrees of freedom by, for example, removing variables which have near-zero variance, or that seems to be not as important as others. Also, if you have some aims in mind, go for it! Don't include variables that might become noise to the model.
To sum up: know your variables first (descriptive analysis), have an aim in mind, and exclude variables which are not really useful for the model.
Hope these ideas help.
Best regards,
Merche Ovejero
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