Table 1.

Descriptive results of the analytical sample.

	Boys (n = 587)	Girls (n = 836)	Overall (N = 1423)
Age
Mean (SD)	15.9 (0.829)	15.8 (0.792)	15.8 (0.809)
Median [Min, Max]	16.0 [14.0, 18.0]	16.0 [13.0, 18.0]	16.0 [13.0, 18.0]
Socio-economic status
Very good	175 (29.8%)	215 (25.7%)	390 (27.4%)
Good	279 (47.5%)	400 (47.8%)	679 (47.7%)
Average good	95 (16.2%)	175 (20.9%)	270 (19.0%)
Not so good	27 (4.6%)	29 (3.5%)	56 (3.9%)
Not good at all	1 (0.2%)	3 (0.4%)	4 (0.3%)
Missing	10 (1.7%)	14 (1.7%)	24 (1.7%)
High school
Bellinzona	139 (23.7%)	205 (24.5%)	344 (24.2%)
Locarno	151 (25.7%)	190 (22.7%)	341 (24.0%)
Lugano	157 (26.7%)	245 (29.3%)	402 (28.3%)
Mendrisio	140 (23.9%)	196 (23.4%)	336 (23.6%)
School year
First	321 (54.7%)	463 (55.4%)	784 (55.1%)
Second	266 (45.3%)	373 (44.6%)	639 (44.9%)
Smartphone type
iPhone	361 (61.5%)	670 (80.1%)	1031 (72.5%)
Android	225 (38.3%)	165 (19.7%)	390 (27.4%)
I don’t have a smartphone of my own	1 (0.2%)	1 (0.1%)	2 (0.1%)