Table 1.

Analysis of variance for the fitted model of BBD.

Source	Sum of Squares	Degree of Freedom	Mean Square	F-Value	p-Value
Model	27.15	14	1.94	168.10	<0.0001 *
X1	7.74	1	7.74	670.94	<0.0001 *
X2	0.13	1	0.13	11.00	0.0051 *
X3	0.12	1	0.12	10.00	0.0069 *
X4	0.07	1	0.07	5.83	0.0300 *
X1X2	7.78 × 10−4	1	7.78 × 10−4	0.067	0.7989
X1X3	0.35	1	0.35	30.53	<0.0001 *
X1X4	0.08	1	0.08	6.80	0.0206 *
X2X3	7.30 × 10−3	1	7.30 × 10−3	0.63	0.4396
X2X4	0.27	1	0.27	23.00	0.0003 *
X3X4	0.14	1	0.14	11.94	0.0039 *
X12	12.23	1	12.23	105.89	<0.0001 *
X22	9.17	1	9.17	79.41	<0.0001 *
X32	0.41	1	0.41	35.66	<0.0001 *
X42	0.57	1	0.57	48.97	<0.0001 *
Residual	0.16	14	0.012	-	-
Lack of fit	0.14	10	0.014	2.88	0.1596
Pure error	0.02	4	4.92 × 10−3	-	-
Cor total	27.31	28	-	-	-

* Significant difference at p < 0.05.