Which design to choose?
HI, I want to study the impact of tempertature and speed on the performance of the product.I want to see also their combined effect.I want to look at three temperatures 120, 140, 160. And three speed 100.150,200. When i do a custom design. its not choosing the mid values. How can I include it. bcos the mid values are the most important ones. Should i go for a screening design or response surface d...