DESIGN AND OPTIMIZATION FOR HAZARDOUS JAROSITE WASTE RECYCLING IN ENVIRONMENTALLY SUITABLE COMPOSITE PRODUCTS USING RESPONSE SURFACE METHODOLOGY - Management of Hazardous Residues Containing Cd - page 74

Table 20 shows the model summary statistics for response compressive
strength. It shows that the special cubic model provides a "Pred R-Squared"
values of 0.9964 which is in excellent agreement with the "Adj R-Squared" of
0.9984. Tables 21,22, 23, 24 and 25 present the model summary statistics for
water

absorption, shrinkage, density leaching of cadmium and lead

respectevelly.
Table 20. Model summary statistics for response compressive strength
Source Std.

Dev.

R-
Squared

Adjusted
R-
Squared

Predicted
R-
Squared

Press

Linear 15.04 0.8524 0.8256 0.7509 4201.27

Quadratic 6.67 0.9789 0.9657 0.9281 1213.12

Special
Cubic

1.43 0.9992 0.9984 0.9964 60.75 Suggested

Cubic 1.67 0.9993 0.9979
The "Pred R-Squared" of 0.9964 is in reasonable agreement with the "Adj R-Squared"
of 0.9984.

Table 21. Model summary statistics for response water absorption
Source Std.

Dev

r 2 Adjusted 2 Predicted r 2 Press

Linear 0.95 0.8816 0.8601 0.7979 17.11

Quadratic 0.54 0.9723 0.9550 0.9140 7.28

Suggested

Special Cubic 0.49 0.9802 0.9632 0.9131 7.35

Cubic 0.58 0.9840 0.9481

Table 22. Model summary statistics for response shrinkage

Source Std. Dev r 2 Adjusted r 2 Predicted r 2

Press

Linear 6.40 0.7583 0.7143 0.5872 770.43

Quadratic 3.08 0.9592 0.9337 0.8715 239.86

Special Cubic 1.82 0.9876 0.9770 0.8846 215.45

Cubic 0.81 0.9986 0.9954