Table 1.
Descriptive Statistics by Sibling Type
| MZ Twin Pairs | DZ Twin Pairs | Full Sibling Pairs | Half-sibling Pairs | Cousin Pairs | Total | |
|---|---|---|---|---|---|---|
| Age (Wave I) | 16.22 (1.62) | 15.98 (1.65) | 16.41 (1.63) | 16.06 (1.84) | 16.44 (1.71) | 16.25 (1.68) |
| Black | 0.21 (0.50) | 0.24 (0.50) | 0.14 (0.50) | 0.35 (0.50) | 0.54 (0.50) | 0.21 (0.41) |
| Hispanic | 0.15 (0.36) | 0.13 (0.33) | 0.16 (0.37) | 0.15 (0.36) | 0.18 (0.39) | 0.15 (0.36) |
| Other race | 0.11 (0.32) | 0.06 (0.24) | 0.15 (0.36) | 0.04 (0.20) | 0.18 (0.37) | 0.11 (0.32) |
| White | 0.53 (0.50) | 0.57 (0.49) | 0.56 (0.50) | 0.46 (0.50) | 0.12 (0.33) | 0.52 (0.50) |
| Male | 0.52 (0.50) | 0.52 (0.50) | 0.51 (0.50) | 0.50 (0.50) | 0.52 (0.50) | 0.52 (0.50) |
| Mean BMI (Wave I) | 21.99 (4.08) | 21.84 (3.82) | 22.44 (4.42) | 22.34 (4.12) | 22.83 (4.14) | 22.25 (4.21) |
| Correlation (BMI) | .82 | .39 | .40 | .10 | .16 | |
| Number of Individuals | 468 | 740 | 1,557 | 403 | 139 | 3,307 |
| Number of Sibling Pairs | 234 | 370 | 864 | 238 | 96 | 1,802 |
Note: all data come from Wave I of the National Longitudinal Study of Adolescent Health (Add Health). Cell entries represent descriptive statistics (means and standard deviations in parentheses) for the pairs sample by sibling type. Correlations within each pair type are provided at the bottom of the table.