“…The (coded) experimental region X is given as: À2 6 x 1 6 2, À2.333 6 x 2 6 2.333, À2.333 6 x 3 6 2.333, À1 6 x 4 6 1, À2.333 6 x 5 6 2.333, À2 6 x 6 6 2, À2.2 6 x 7 6 2.2, À2.5 6 x 8 6 2.5. The estimated response models (Palmer et al, 2006) are given below:…”