Table 1.

Description of the sample according to demographic variables (grade, gender, socioeconomic status, religion, Parents’ education, and residence). San Felipe, Chile (year of data collection: 2012).

Variable	n	Percentage (%)	95% Confidence interval
Level (grade)
9	149	26.0	22.4	29.6
10	143	25.0	21.4	28.5
11	140	24.5	20.9	28.0
12	140	24.5	20.9	28.0
Gender
Female	248	43.4	39.3	47.4
Male	324	56.6	52.6	60.7
Socioeconomic status
High	219	38.3	34.3	42.3
Middle	199	34.8	30.9	38.7
Low	154	26.9	23.3	30.6
Religion
Catholic	430	75.2	71.6	78.7
Christian or Evangelical	60	10.5	7.9	1.3
Mormon	3	0.5	0.0	1.1
Jehovah’s Witness	3	0.5	0.0	1.1
Other	10	1.8	0.1	2.8
None	66	11.5	0.9	1.4
Father's education
None	7	1.2	0.3	2.1
Incomplete primary	39	6.8	4.7	8.9
Complete primary	42	7.3	5.2	9.5
Incomplete secondary	56	9.8	7.3	12.2
Complete secondary	181	31.7	27.8	35.5
Incomplete higher	29	5.1	3.3	6.9
Complete higher	179	31.3	27.5	35.1
I don’t know	36	6.3	4.3	8.3
Other studies	3	0.5	0.0	1.1
Mother’s education
None	2	0.3	−0.1	0.8
Incomplete primary	39	6.8	4.8	8.9
Complete primary	35	6.1	4.2	8.1
Incomplete secondary	68	11.9	9.2	14.5
Complete secondary	185	32.3	28.5	36.2
Incomplete higher	44	7.7	5.5	9.9
Complete higher	161	28.1	24.4	31.8
I don't know	34	5.9	4.0	7.9
Other studies	4	0.7	0.0	1.4
Place of residence
Urban	408	71.3	67.6	75.0
Rural	164	28.7	24.9	32.4
		Mean (SD)	Median (IQR)
Age	569	16.4 (1.3)	16.4 (15.4–17.4)