How to account for tank to tank variability: Whole-plot factor, covariate, blocking?
I want to run a screening DOE to ID factors important for yield in a batch process. I have 4 tanks (call them A, B, C, D) to do it in, and want to investigate 5 continuous factors impact on my 1 response. However, I discovered that there is significant variability between the 4 tanks - with 1 tank consistently having significantly lower yield than 1 other tank (highest producing tank), while the o...