Table 1.
Characteristics of participants.
| n | % | |
|---|---|---|
| Sex | ||
| Male | 179 | 51.1 |
| Female | 171 | 48.9 |
| Age | ||
| 5 years | 42 | 12.0 |
| 6 years | 130 | 37.1 |
| 7 years | 118 | 33.7 |
| 8 years | 60 | 17.1 |
| Paternal employment status | ||
| Daily labor | 7 | 2.0 |
| Employee | 43 | 12.5 |
| Owner-operator | 52 | 15.1 |
| Office worker | 130 | 37.7 |
| Middle manager | 84 | 24.3 |
| Professional/senior manager | 20 | 5.8 |
| Artist/region worker | 7 | 2.0 |
| Homemaker /no employment | 2 | .6 |
| Maternal employment status | ||
| Daily labor | 4 | .9 |
| Employee | 26 | 7.4 |
| Owner-operator | 21 | 6.0 |
| Office worker | 73 | 20.9 |
| Middle manager | 11 | 3.1 |
| Professional/senior manager | 24 | 6.9 |
| Artist/region worker | 14 | 4.0 |
| Homemaker /no employment | 178 | 50.9 |
| Monthly household income | ||
| KRW <4,000,000 | 112 | 32.0 |
| KRW ≥4,000,000 | 238 | 68.0 |
| Main caregiver | ||
| Parents | 332 | 94.9 |
| Grandparents or other | 18 | 5.1 |
| Starting age of smartphone usage | ||
| 0–11 months | 19 | 6.8 |
| 12–23 months | 62 | 22.1 |
| 24–35 months | 41 | 14.6 |
| 36–47 months | 39 | 13.9 |
| 48–59 months | 25 | 8.9 |
| ≥60 months | 94 | 33.6 |
| Location of smartphone use | ||
| Home | 183 | 65.1 |
| Other | 98 | 34.9 |
| Smartphone co-user | ||
| Parents | 113 | 40.2 |
| Other | 168 | 59.8 |
n = 350. KRW = South Korean won.