Hi, I developed a DOE model with 3 factors (one categorical) for a specific time (7 days) containing 16 runs. Later I used the same DOE but now for samples (runs) with a loger time (28 days). Now, I have decided to add the time as a factor but I want to keep the runs that a I have (16 runs for 7 days, and 16 runs for 28 days); to improve the quality of the model I decided to add center points to the design (time 17.5 days): I added 4 runs, one for each value of the categorical factor. How can I do that, keeping some previous runs? In the augmented design it is not allowed to add a new factor, or is it allowed (if yes, I do not know how to do it). So, I decided to develop a new DOE, now with 4 factors (including time as a factor) and with 30 runs (16 for 7 daus, 4 for 17.5 days, 16 for 28 days), but the table generated by jmp has some runs different from the previous 16 runs (for 7 and 28 days); can I change the values of any factor in this new DOE in order to keep the previous runs, is this alllowed wtihout compromising the accuracy? Or simply I cannot perform this analysis?
