Table 12.

ANOVA of central composite experiment

	Sum of squares	Mean square	F-ratio	Prob>F
Linear	5465.10	0.0834	2.64	0.1398
Quadratic	46171.00	0.7050	22.31	0.0009
Crossproduct	6609.69	0.1009	6.39	0.0394
Total regress	58246.00	0.8894	11.26	0.0031
Lack-of-fit	6671.77	2223.9200	15.52	0.0114
Pure error	573.34	143.3300
Total error	7245.11	1035.0200

Response mean=1221.92; RMSE=32.17; R ²=0.898; CV=2.6329