Table 6.

Regression analysis via IPI score.

	Least square regression			Probit regression
	Coefficient	Z value	p value	Coefficient	Z value	p value
(Int)	6.6774	4.787	0.000	0.4238	1.19	0.2342
Sex	−0.0010	−0.007	0.9942	−0.0002	−0.006	0.9951
Age	−0.0186	−5.285	0.000	−0.0047	−5.26	0.000
Height	−0.0060	−0.679	0.4975	−0.0015	−0.671	0.5023
Weight	0.0061	1.068	0.2859	0.0016	1.059	0.2901
Surgical history	−0.1088	−0.673	0.5013	−0.0278	−0.675	0.4997
Past history	0.0299	0.231	0.817	0.0077	0.234	0.8148
Smoking history	0.2302	1.781	0.0753.	0.0588	1.775	0.0762.
Sedative drugs	0.4159	4.075	0.000	0.1059	4.063	0.000
Total sedative dose	0.0005	1.007	0.3141	0.0001	1.006	0.3146