Table 1.
Sample descriptives (n = 3,038) of demographics and covariates at the beginning of 6th grade (age 11) and physical aggression behaviors over time
| Variables | Mean | SD | Proportion | Minimum | Maximum |
|---|---|---|---|---|---|
| Demographics/covariates | |||||
| Age | 11.84 | 0.57 | – | 10.34 | 14.34 |
| Male | – | – | 0.51 | 0.00 | 1.00 |
| Black | – | – | 0.38 | 0.00 | 1.00 |
| Hispanic | – | – | 0.33 | 0.00 | 1.00 |
| US born | – | – | 0.85 | 0.00 | 1.00 |
| Low socioeconomic status |
– | – | 0.80 | 0.00 | 1.00 |
| Natural parent household |
– | – | 0.56 | 0.00 | 1.00 |
| Delinquent peersa | 0.50 | 0.87 | – | 0.00 | 4.00 |
| Unsupervised timeb |
1.71 | 1.44 | – | 0.00 | 4.00 |
| Prior police contact |
– | – | 0.09 | 0.00 | 1.00 |
| Alcohol and substance use | |||||
| Past year alcohol use |
– | – | 0.16 | 0.00 | 1.00 |
| Ever smoking | – | – | 0.10 | 0.00 | 1.00 |
| Past year marijuana use |
– | – | 0.06 | 0.00 | 1.00 |
| Physical aggression behaviors | |||||
| Baselinec | 2.62 | 2.36 | – | 0.00 | 8.00 |
| 6th grade (Age 12)c |
3.05 | 2.49 | – | 0.00 | 8.00 |
| 7th grade (Age 13)c |
3.27 | 2.44 | – | 0.00 | 8.00 |
| 8th grade (Age 14)c |
3.27 | 2.49 | – | 0.00 | 8.00 |
a
Range: 0–4; a higher score on this scale indicates a higher number of delinquent friends
b
Range: 0–4; a higher score on this scale indicates a higher number of hours without adult supervision
c
Range: 0–8; a higher score on this scale indicates higher physical aggression