Table 3.

Inclusion frequencies of the independent variables in each part of the model of tobacco use

	Part 1: probability of smoking		Part 2: quantity smoked by smokers
Variable	% retained	Rank	% retained	Rank
Cannabis use	100.0	1	76.9	7
Position about smoke-free universities	99.8	2	90.6	2
Perceived friends' approval of regular smoking	97.7	3	90.2	3
Tobacco perception score	94.4	4	41.8	25
Perceived prevalence of smoking among friends	92.2	5	65.1	14
Frequency of being disturbed by people smoking in university	90.1	6	98.6	1
Binge drinking	86.7	7	49.6	22
Gender	84.3	8	53.9	20
Attitudes towards tobacco industry score	79.5	9	44.9	24
Knowledge of university tobacco policy	76.8	10	32.3	30
Parents together	74.5	11	46.2	23
Smoking prevalence in class	72.7	12	69.1	11
Perceived friends' approval of occasional smoking	66.4	13	54.8	18
Alcohol use	66.3	14	71.8	9
Number of friends	66.2	15	67.0	13
Cannabis use prevalence in class	54.0	16	75.7	8
BMI	53.2	17	36.6	28
Perceived smoking prevalence by peer students	51.6	18	70.2	10
Perceived exposure to tobacco prevention campaigns	51.4	19	60.0	16
Tobacco prevention campaigns perception score	50.8	20	67.4	12
Perceived friends' approval of smoking experimentation	48.4	21	55.9	17
Academic discipline	47.8	22	82.0	6
Binge drinking prevalence in class	41.0	23	39.2	27
Partner status (having one partner or not)	39.0	24	50.0	21
Number of friends in class	33.3	25	54.8	18
Age	30.7	26	83.9	4
Previous exposure to substance-use questionnaires	30.0	27	61.3	15
Final high school exam grade	29.7	28	35.1	29
Alcohol drinking prevalence in class	29.6	29	31.2	31
Self-esteem score	25.7	30	39.7	26
Beliefs about tobacco industry score	25.5	31	83.8	5