Surface response designs
Surface response designs allow identifying factor values that minimize or maximize a response. Available in Excel using the XLSTAT software.
The family of surface response design is used for modeling and analysis of problems in which a response of interest is influenced by several variables and the objective is to optimize this response.
Remark: In contrast to this, screening designs aim to study the input factors, not the response value.
For example, suppose that an engineer wants to find the optimal levels of the pressure (x1) and the temperature (x2) of an industrial process to produce concrete, which should have a maximum hardness y.
XLSTAT includes Central Composite, Box Behnken and Doehlert designs.