Table 3.

Coefficient estimates in the regression model for rhamnolipid yield selected through variable selection (a) and ANOVA for rhamnolipid yield (b)

a
Variable	Coefficient	Standard error	t	p
Constant	10.717	0.178	60.16	0.000*
Oil	0.241	0.109	2.21	0.039*
CFP	1.009	0.109	9.25	0.000*
KH2PO4	0.587	0.109	5.39	0.000*
Oil*Oil	−1.393	0.161	−8.67	0.000*
CFP*CFP	−1.318	0.161	−8.21	0.000*
KH2PO4*KH2PO4	−2.111	0.161	−13.15	0.000*
Oil*CFP	−0.131	0.154	−0.85	0.405
Oil*KH2PO4	0.288	0.154	1.86	0.077
CFP*KH2PO4	0.213	0.154	1.38	0.184

b
Source	Degree of freedom	Sum of squares	Mean squares	F	p
Model	9	76.5844	8.5094	44.70	0.000
Linear	3	22.7503	7.5834	39.84	0.000
Square	3	52.6737	17.5579	92.23	0.000
Interaction	3	1.1603	0.3868	2.03	0.142
Residual Error	20	3.8074	0.1904
Lack-of-Fit	3	0.7928	0.2643	1.49	0.253
Pure Error	17	3.0146	0.1773
Total	29	80.3917

S: 0.4363, R ²: 95.26%, R ²(pred): 90.45%, R ² (adj): 93.13%