Enhancement of Cellulase Activity from a New Strain of Bacillus subtilis by Medium Optimization and Analysis with Various Cellulosic Substrates

Table 5

Model coefficient estimated by multiple linear regressions.

Model term	Parameter estimate	Standard error	Computed t-value	𝑃-value
Intercept	0.270187	0.004467	60.479	.000
𝑋1 (CMC)	0.151937	0.004985	30.480	.000
𝑋2 (Peptone)	0.019066	0.004985	3.825	.003
𝑋3 (Yeast extract)	0.050437	0.004985	10.118	.000
𝑋1^2	0.000199	0.008161	0.024	.981
𝑋2^2	0.017596	0.008161	2.16	.056
𝑋3^2	−0.045086	0.008161	−5.524	.000
𝑋1∗𝑋2	0.035305	0.010954	3.223	.009
𝑋1∗𝑋3	−0.049972	0.010954	−4.562	.001
𝑋2∗𝑋3	−0.005799	0.010954	−0.529	.608