Problem with adding midpoints to my design (they are not randomly distributed)
Dear Community,
I have created a design with 12 factors, 11 of them are continuous and the last one is discrete numeric with three levels. I decided to add 30 midpoints (see attached screenshot of the experimental design). Why are the factors of the midpoints not randomly distributed?
I tried the model with fewer factors, and the midpoints were randomly distributed as desired.
I also tried increasin...