Table 1. Baseline characteristics of the study participants (n = 400).
| Variables | Boys (n = 207) | Girls (n = 193) | P valuea | ||
|---|---|---|---|---|---|
| Age | 0.678 | ||||
| 2 | 31 (14.9) | 31 (16.1) | |||
| 3 | 86 (41.5) | 82 (42.5) | |||
| 4 | 69 (33.3) | 67 (34.7) | |||
| 5 | 21 (10.1) | 13 (6.7) | |||
| Main caregiver | 0.393 | ||||
| Parents | 191 (93.2) | 182 (94.8) | |||
| Grandparents | 10 (4.9) | 9 (4.7) | |||
| Others | 6 (2.9) | 2 (1.0) | |||
| Paternal education (n = 399) | 0.651 | ||||
| High school or below | 24 (11.7) | 22 (11.3) | |||
| College or above | 182 (88.3) | 171 (88.6) | |||
| Maternal education | 0.032 | ||||
| High school or below | 35 (17) | 15 (7.8) | |||
| College or above | 172 (83.1) | 178 (92.2) | |||
| Paternal employment status (n = 396) | 0.515 | ||||
| Unemployed | 4 (2) | 2 (1) | |||
| Employed | 200 (98) | 190 (99) | |||
| Maternal employment status (n = 399) | 0.245 | ||||
| Unemployed | 130 (62.8) | 123 (64.1) | |||
| Employed | 77 (37.2) | 69 (35.9) | |||
| Monthly household income, KRW | 0.391 | ||||
| < 4,000,000 | 101 (48.8) | 97 (50.3) | |||
| ≥ 4,000,000 | 106 (51.2) | 96 (49.7) | |||
| Ownership of media devices | |||||
| First wave (2015) | |||||
| TV | 194 (94.2) | 185 (96.9) | 0.199 | ||
| Tablet PC | 95 (47) | 94 (49.5) | 0.628 | ||
| Smartphone | 196 (96.1) | 187 (97.9) | 0.290 | ||
| Second wave (2016) | |||||
| TV | 187 (94.9) | 176 (97.2) | 0.299 | ||
| Tablet PC | 94 (47.7) | 103 (57.2) | 0.079 | ||
| Smartphone | 197 (100) | 177 (98.3) | 0.108 | ||
| Third wave (2017) | |||||
| TV | 180 (96.7) | 167 (94.3) | 0.312 | ||
| Tablet PC | 120 (64.8) | 114 (64.7) | 1.000 | ||
| Smartphone | 172 (92.4) | 160 (90.4) | 0.574 | ||
Values are presented as number (%).
aAnalysis of χ2-test for categorical variables.