Hello everyone. I have a question related to DOE.
When conducting a Lack of fit test, how should the F ratio be calculated? F=MS residual /MS pure eror or
F=MS lack of fit/MS pure eror. The idea is to compare the model error with the experimental error..
Are the results obtained from the two formulas different? Which result is more reliable and when is it necessary to use each of the two formulas?
The first formula gives a lower value of f compared to the second formula for the same data.
I would be grateful if someone could clarify this issue.
Best regards, Milen
