Table 2.

Statistical analysis of Plackett Burman design showing coefficient values, t- and P-value for each variable.

Variable	Coefficient	t-Stat	P-value	Confidence level (%)
Intercept	0.107817	15.96	.000	100
CMC (X1)	0.083852	12.41	.000	100
Peptone (X2)	0.020703	3.06	.01	99
Yeast Extract (X3)	0.024881	3.68	.003	99.7
K2HPO4  (X4)	0.005974	0.88	.394	60.6*
MgSO4·7H2O (X5)	−0.005107	−0.76	.464	53.6*
FeSO4·7H2O (X6)	−0.009733	−1.44	.175	82.5*
MnCl2·4H2O (X7)	0.001163	0.17	.866	13.4*

*Insignificant values.