Table 1.
Demographic data.
| Boys (N=38,391, 52.4%) | Girls (N=34,847, 47.6%) | Total (N=73,238, 100%) | t/χ2, p, Cramer’s V | |
|---|---|---|---|---|
| Age (years) | 15.1±1.7 | 15.1±1.8 | 15.1±1.7 | t=1.5, p=0.14 |
| School gradea | χ2=23.7, p<0.01, V=0.02 | |||
| 1st middle school | 6519 (17.0) | 5949 (17.1) | 12,468 (17.0) | |
| 2nd middle school | 6620 (17.2) | 5879 (16.9) | 12,499 (17.1) | |
| 3rd middle school | 6817 (17.8) | 5786 (16.6) | 12,603 (17.2) | |
| 1st high school | 6229 (16.2) | 5792 (16.6) | 12.021 (16.4) | |
| 2nd high school | 6273 (16.3) | 5851 (16.8) | 12,124 (16.6) | |
| 3rd high school | 5933 (15.5) | 5590 (16.0) | 11,523 (15.7) | |
| Economic statea | χ2=383.9, p<0.01, V=0.07 | |||
| Rich | 12,238 (31.9) | 8834 (28.8) | 21,072 (28.8) | |
| Average | 17,061 (44.4) | 17,192 (49.3) | 34,253 (46.8) | |
| Poor | 9092 (23.7) | 8821 (25.3) | 17,913 (24.5) | |
| Stressa | 3.3±1.0 | 3.5±0.9 | 3.4±1.0 | t=40.5, p<0.01 |
| Depressed mooda | ||||
| Yes/No | 12,366 (32.2)/26,025 (67.8) | 15,007 (43.1)/19,840 (56.9) | 27,373 (37.4)/45,865 (62.6) | χ2=919.5, p<0.01, V=0.11 |
| Suicidal ideationa | ||||
| Yes/No | 5855 (15.3)/32,536 (84.7) | 8156 (23.4)/26,691 (76.6) | 14,001 (19.3)/59,227 (80.7) | χ2=785.1, p<0.01, V=0.10 |
| Internet use | ||||
| WKD (use/non-use)a | 25, 612 (66.7)/12,779 (33.3) | 25, 706 (73.8)/9141 (26.2) | 51,318 (70.1)/21,920 (29.9) | χ2=433.5, p<0.01, V=0.08 |
| WKD (use time/min)a | 123±103 | 113±87 | 118±96 | |
| WED (use/non-use)a | 28,882 (75.2)/9509 (24.8) | 27,574 (79.1)/7273 (20.9) | 56,456 (77.1)/16,782 (22.9) | χ2=157.1, p<0.01, V=0.05 |
| WED (use time/min)a | 197±131 | 163±109 | 181±122 | |
| General users | 31,574 (82.2) | 30,746 (88.2) | 62,320 (85.1) | χ2=559.7, p<0.01, V=0.09 |
| Potential riska | 5305 (13.8) | 3417 (9.8) | 8722 (11.9) | |
| High riska | 1512 (3.9) | 2194 (2.0) | 2196 (3.0) | |
| Alcohol (use/non-use)a | 9040 (23.5)/29,351 (76.5) | 6515 (18.7)/28,332 (81.3) | 15,555 (21.2)/57,683 (78.8) | χ2=256.9, p<0.01, V=0.06 |
| Smoking (use/non-use)a | 6482 (16.9)/31,909 (83.1) | 2455 (7.0)/32,392 (93.0) | 8937 (12.2)/64,301 (87.8) | χ2=256.9, p<0.01, V=0.15 |
| Drugs (use/non-use)a | 814 (2.1)/37,577 (97.9) | 586 (1.7)/34,261 (98.3) | 1400 (1.9)/71,838 (98.1) | χ2=18.7, p<0.01, V=0.02 |
a
Statistically significant (p<0.01, V<0.3), WKD: week day, WED: weekend, post hoc Cramer’s V coefficient.