Table 3.

Statistics of the variables chosen following the CART training. Labels are as in original dataset (Yamamoto, 2020).

	All	Female	Male
Total respondents	11,342	5608 (49.44%)	5734 (50.56%)
Marital status
1. Married	4722 (41.63%)	2229 (39.75%)	2493 (43.48%)
2. Not married	6620 (58.37%)	3379 (60.25%)	3241 (56.52%)
Having children younger than junior high school age
1. No	2972 (26.20%)	1479 (26.38%)	1493 (26.04%)
2. Yes	8370 (73.80%)	4129 (73.62%)	4241 (73.96%)
Smoking frequency
1. Never smoked	6748 (59.50%)	4120 (73.47%)	2628 (45.83%)
2. Used to smoke but not now	2188 (19.29%)	773 (13.78%)	1415 (24.68%)
3. Sometimes	270 (2.38%)	82 (1.46%)	188 (3.28%)
4. Everyday	2136 (18.83%)	633 (11.29%)	1503 (26.21%)
Work status
1. Regular employee	5817 (51.29%)	1831 (32.65%)	3986 (69.52%)
2. Non-regular employee	2865 (25.26%)	2132 (38.02%)	733 (12.78%)
3. Self-employed and others	660 (5.82%)	238 (4.24%)	422 (7.36%)
4. Not working	2000 (17.63%)	1407 (25.09%)	593 (10.34%)