Optimization of Tree-Based Machine Learning Models to Predict the Length of Hospital Stay Using Genetic Algorithm

Table 3

Statistical characteristics of variables in the studied sample.

No.	Variable	n	Mean ± SD/percent
1	Age (year)	200	63 ± 19
2	Sex
3	Female	100	50%
4	Male	100	50%
5	Marital status
6	Married	179	90%
7	Single	21	11%
8	Main insurance type
9	Ordinary social security insurance (ordinary SSI)	180	90%
10	Occupational social security insurance (occupational SSI)	5	3%
11	Employee health insurance (employee HI)	3	2%
12	Special social security insurance (special SSI)	6	3%
13	Without insurance (without insurance)	6	3%
14	Physician expertise level
15	General practitioner	90	45%
16	Specialist	107	54%
17	Subspecialty physician	3	2%
18	Medical advice no		2 ± 3
19	LOS (day)		5.6 ± 3.4