Table 1. Distribution over socio-demographic characteristics from the whole sample (N = 439) and from the subgroup of study participants with operator recorded data (N = 233).
| N = 439 | Prop(%) | N = 233 | Prop(%) | |
|---|---|---|---|---|
| Age (years) | ||||
| 12–13 | 44 | 10.0 | 28 | 12.0 |
| >13–14 | 200 | 45.6 | 105 | 45.1 |
| >14–15 | 142 | 32.3 | 80 | 34.3 |
| >15 | 53 | 12.1 | 20 | 8.6 |
| Sex | ||||
| Female | 265 | 60.4 | 150 | 64.4 |
| Male | 174 | 39.6 | 83 | 35.6 |
| Class level | ||||
| 7th grade | 105 | 23.9 | 52 | 22.3 |
| 8th grade | 293 | 66.8 | 172 | 73.8 |
| 9th grade | 41 | 9.3 | 9 | 3.9 |
| School level | ||||
| College preparatory high school | 99 | 22.5 | 66 | 28.3 |
| High School | 340 | 77.5 | 167 | 71.7 |
| Nationality | ||||
| Swiss | 348 | 79.3 | 189 | 81.1 |
| Swiss and other | 62 | 14.1 | 31 | 13.3 |
| Other | 29 | 6.6 | 13 | 5.6 |
| Physically active | ||||
| Yes | 379 | 86.3 | 202 | 86.7 |
| Number of days with alcohol consumption | ||||
| None | 304 | 69.2 | 156 | 67.0 |
| One or less than one per month | 99 | 22.6 | 55 | 23.6 |
| More than one per month | 36 | 8.2 | 22 | 9.4 |
| Highest education of parents | ||||
| No education | 3 | 0.7 | - | - |
| Mandatory school / High school | 9 | 2.0 | 4 | 1.7 |
| Training school | 233 | 53.1 | 118 | 50.6 |
| College preparatory high school | 29 | 6.6 | 14 | 6.0 |
| College of higher education | 130 | 29.6 | 78 | 33.5 |
| University | 35 | 8.0 | 19 | 8.2 |
| Frequency [x/d] of mobile phone calls (self-reported; N = 439) | ||||
| never; 0 x/d | 27 | 6.1 | - | - |
| >0 to ≤0.5 x/d | 216 | 49.2 | - | - |
| >0.5 to ≤1 x/d | 71 | 16.2 | - | - |
| >1 to ≤5 x/d | 115 | 26.2 | - | - |
| >5 x/d | 10 | 2.3 | - | - |
| Duration [min/d] of operator recorded mobile phone calls (N = 233) | ||||
| ≤1 min/day | - | - | 151 | 64.8 |
| >1 to ≤2 min/day | - | - | 36 | 15.4 |
| >2 to ≤5 min/day | - | - | 26 | 11.2 |
| >5 to ≤10 min/day | - | - | 12 | 5.2 |
| >10 min/day | - | - | 8 | 3.4 |