Table 5.

The results of multiple regressions and the significance for RSM model terms.

		Factor	Standard error	t-value #	P-value	Contributions (%)
Main effects	Linear	$T$	0.66	15.09	0.0006***	11.28
	Linear	$P_{\text{CO}}$	0.66	41.16	0.0001***	83.92
	Linear	$P_{{\text{H}}_2}$	0.66	6.31	0.0249**	1.97
Interaction	Cross product	$T\times P_{\text{CO}}$	0.93	6.1	0.0285**	1.83
		$T\times P_{{\text{H}}_2}$	0.93	0.56	0.7896	0.015
		$P_{\text{CO}}\times P_{{\text{H}}_2}$	0.93	1.55	0.4727	0.12
	Pure quadratic	$T^2$	0.97	-2.78	0.222	0.38
		$P_{\text{CO}}^2$	0.97	-2.23	0.3147	0.24
		$P_{{\text{H}}_2}^2$	0.97	-2.12	0.3351	0.22

^#t-value = twice coefficient estimated /standard error.

*significant at 10% (p-value),**Significant at 5% (P-value),***significant at 1% (P-value).