Table 4

The SPSS version 11.0 multiple regression output for regression coefficients

Model	Variable^*	Unstandardized coefficients		Standardized coefficient	t	p value

		B	SE	β
1	(Constant)	23.95	3.32	—	7.21	< 0.001

	IDS	2.78	0.13	0.67	21.86	< 0.001

2	(Constant)	−27.70	6.81	—	−4.07	< 0.001

	IDS	2.27	0.13	0.55	16.90	< 0.001

	Team size	8.07	0.95	0.28	8.54	< 0.001

3	(Constant)	−20.23	7.80	—	−2.59	0.010

	IDS	2.29	0.13	0.55	16.97	< 0.001

	Team size	7.14	0.98	0.24	7.31	< 0.001

	ASA class	7.92	2.13	0.12	3.73	< 0.001

	Age of patient	−0.30	0.09	−0.10	−3.15	0.002

ASA = American Society of Anesthesiologists; IDS = index of difficulty of surgery; SE = standard error.
↵* The dependent variable is procedure length.