In Equation (2), y represents the plant’s biological response (%Yield) to the addition of compounds, B0 is the intercept term for the quadratic equation, Bn is the coefficient for the nth compound, and Bmn is the interaction terms between mth and nth compound. xn indicates the concentration levels (0, 1, or 2) of a given compound.
The WisDM Green second order quadratic series was derived from stepwise regression that performed bidirectional elimination of the estimated coefficients using the P values from F-statistics in MATLAB 2020b (Mathworks, Inc.). This quadratic series was then used to derive the predicted %Yield data for all possible combinations consisting of 8 compounds in three concentration levels (38 = 6,561). Box-Cox transformation was explored to determine appropriate transformations to the %Yield output data. Residual-based outlier analysis was performed based on the residual distribution of the %Yield data.