TABLE 1—
Descriptive Characteristics of Third-Grade Children: United States, Early Childhood Longitudinal Study, Kindergarten Class of 1998–1999
| Variable | Mean or % (SE) |
| Gender | |
| Female | 49.89 (0.009) |
| Male | 50.11 (0.009) |
| Race/ethnicity | |
| White | 60.53 (0.018) |
| Black | 13.36 (0.010) |
| Hispanic | 19.19 (0.014) |
| Asian/Pacific Islander | 3.38 (0.003) |
| American Indian | 1.44 (0.009) |
| Multiracial | 2.14 (0.003) |
| Age, y | 9.102 (0.004) |
| Physical activity | |
| No sports | 24.78 (0.009) |
| Individual sports only | 10.51 (0.006) |
| Group sports only | 27.58 (0.010) |
| Both group and individual sports | 37.14 (0.010) |
| Parents in household | |
| Mother and father | 60.90 (0.011) |
| Mother only | 21.08 (0.009) |
| Mother and stepfather | 10.79 (0.007) |
| Adopted | 4.30 (0.005) |
| Father only | 1.82 (0.003) |
| Father and stepmother | 1.09 (0.002) |
| Mother works full time | 48.39 (0.010) |
| Maternal depression | 23.93 (0.009) |
| SES quintile | |
| 1 (Lowest) | 17.86 (0.010) |
| 2 | 19.78 (0.009) |
| 3 | 20.63 (0.008) |
| 4 | 20.79 (0.007) |
| 5 | 20.94 (0.010) |
Note. SES = socioeconomic status. Data were from the 2002 third-grade wave, adjusted to represent the US population of children who entered kindergarten and first grade in 1998 and 1999. Sample size for this analysis was n = 8346.