Residual analysis DOE
Dear community, I would like to ask for a bit of support on the interpretation of raw residuals. I analyzed data using 3K factorial with 3 factors and three levels, total runs 27. I got the next raw residuals vs predicted values. I am not pretty sure that the plot is ok, the variance seems quite equal from negative and positive a small pattern in the center I am not sure if there is a big issue. i...