Hi @Barjas87,
It's very difficult to answer your question, regarding the lack of context, information, and data you provide. I'm not even sure how it may relate to DoE, factors range, topics of interpolation/extrapolation, or only about regression models, etc...
It's also the third time your post has the same minimalist title "What", which clearly doesn't help and/or motivate other members to read and answer to your post.
In order to help you have faster and better answers, here are 2 helpful posts that @jthi and @LandraRobertson created that can guide you in your post/questions writing :
Getting correct answers to correct questions quickly
Getting fast helpful answers to your questions
I hope this will help you, looking forward to reading more details in order to help you !
PS: Did you had the time to read my answer to your previous post about optimality : Re: What - JMP User Community
Did it help you ?
Victor GUILLER
"It is not unusual for a well-designed experiment to analyze itself" (Box, Hunter and Hunter)
