response surface issued by Cox and Wilson in 1950, this design is to display the relationship between multiple factors and the outcomes. It try to understand what situations (combination of the factors and their conditions ) can generate the optimal outcome. The first degree polynomial was suggested to construct the response to approximate the surface. The easiest way of accomplishing the first degree polynomial is to use the factorial experimental design, which can determine which factor has the what effect on the outcome. After model selection, the final model including only the only significant factors can be achieved. A further quadratic or cubic model can be fit to those factors to approximate the outcomes. In Rubin's work. the nonlinear response surface was due to the nonlinear relationship of the X, the matching variables, and Y.