Hi everyone, I am Dario and I am a PhD student. I am new in DOE tecnique and this is the reason why I am asking you help. I must provide a DOE tecnique in order to obtain an analytical correlation... in particular, I have 3 factors (A,B,C) and 3 level for each one. A 0.59 0.69 0.77 B 16.2 24.2 32.2 C 3.2 3.4 3.6 I am using the book "Design and Analysis Experiments" by Douglas C. Montgomery; I read that "the 3^k design is not the most efficient way to model a quadratic relationship" and that is better use this sequential strategy: - Use 2^k design augmented with center points and obtain an indication of curvature; - If the curvature is important, augment the 2-level design with axial runs to obtain a CCD. Can someone explain me clearly how to procede with this strategy? Maybe with an example?? I don't have much time unluckly to study all the book because my advisor give me only 3 days to solve this issue. So I really appreciate if someone could help me. Thank you, in advance.