Code=variables (Unit)  “better to best” Independent (Space=Coded) Levels
X1=PDAB(ml) 4.00 (-1=1) 5.00 (0=2) 6.00 (+1=3)
X2= FeCl3 (ml) 5.00 (-1=1) 6.00 (0=2) 7.00 (+1=3)
Dependant Constraints
Y1 = Absorbance 0.56≤Y­1≥0.71
Design Results
Runs-Code Variables
Independent Dependent (Y1) Response (R1)
X1 X2 Observed Predicted
BB-1 1.00 1.00 0.665 0.670
BB-2 2.00 1.00 0.571 0.570
BB-3 3.00 1.00 0.601 0.600
BB-4 1.00 2.00 0.640 0.640
BB-5 1.00 3.00 0.592 0.590
BB-6 2.00 3.00 0.581 0.580
BB-7 3.00 2.00 0.658 0.660
BB-8 2.00 2.00 0.586 0.590
BB-9 2.00 2.00 0.590 0.590
BB-10 2.00 1.00 0.564 0.570
BB-11 2.00 2.00 0.590 0.590
BB-12 2.00 2.00 0.589 0.590
BB-13 3.00 3.00 0.705 0.700
Surface Design (3D) Best Model
Terms Model X1 X2 X1X2 X12 X22 Lack of Fit
F value 383.4 63.4 33.40 691.65 1061.8 37.20 1.70
Intercept 0.59 0.011 0.0076 0.0445 0.064 -0.012  
p. value (Prob>F) 0.0001 0.0007 . < 0.0001 < 0.0001 0.0005 0.3040
R-Square Adjusted R2 Predicted R2 Std. Dev %CV
0.996 0.994 0.982 0.0035 0.67
F-value Less than 0.0500 indicate model terms are significant and Lack of fit value Greater than 0.1000 indicate the model terms are not significant
Table 2: Result Of Quadratic Design Methodology.