Table 1.
Sample Characteristics
| Measure | NL | US | Difference | Test Statistic | p |
|---|---|---|---|---|---|
|
| |||||
| Total n | 24 | 24 | |||
| Infant sex (percent male) | 53% | 69% | 16% | X2=1.02 | .31 |
| Infant birth order (percent first) | 52% | 52% | 0% | X2=0.00 | ns |
| Infant age at observation (median) | 8.33 | 8.43 | 0.10 | z = 0.32 | .75 |
| Percent recordings on weekend | 17% | 9% | 8% | X2=.77 | .38 |
| Father’s Hollingshead Occupation Score (median) | 3.0 | 3.0 | 0 | z = 0.00 | ns |
| Mother’s age (years) | 28.7 | 33.4 | 4.7 | t=−3.05 | .004 |
| Mother’s education (years) | 15.0 | 17.3 | 2.3 | t=−3.35 | .002 |
| Mother’s employment | |||||
| Full time (>=35 h/week) | 9% | 52% | X2=11.03 | .004 | |
| Part-time (< 35 h / week) | 50% | 14% | |||
| Not employed | 41% | 33% | |||
| Hours of non-maternal care (7 am - 7pm) (median) | 0.98 | 2.97 | 1.99 | z = 1.70 | .09 |
| Percent non-maternal care by: | |||||
| employee | 21% | 43% | |||
| father | 43% | 30% | X2 = 4.24 | .12 | |
| other relative | 36% | 26% | |||
| Usual location of initial putting to sleep at night | |||||
| Baby’s room | 81% | 89% | |||
| Parents’ room | 5% | 5% | Fisher’s Exact | .54 | |
| Other room (e.g. living room) | 14% | 6% | |||
| Usual location of daytime naps | |||||
| Baby’s room | 66% | 73% | |||
| Parents’ room | 5% | 0% | |||
| Other room (e.g. living room) | 13% | 19% | Fisher’s Exact | .09 | |
| Outside | 16% | 0% | |||
| In car | 0% | 8% | |||