Response surface methodology (RSM) can be used when the response variable, y, is influenced by several variables, x’s. When treatments take the form of quantitative values, then the true relationship between response variables and independent variables might be known. Examples are given in SAS.
Amir, Wan Muhamad; Shafiq, Mohamad; Mokhtar, Kasypi; Aleng, Nor Azlida; A.Rahim, Hanafi; and Ali, Zalila
"Simple Response Surface Methodology Using RSREG (SAS),"
Journal of Modern Applied Statistical Methods:
1, Article 44.
Available at: http://digitalcommons.wayne.edu/jmasm/vol15/iss1/44