Table 2.
Descriptive statistics of sample.
| Characteristic | School 1 n = 144 | School 2 n = 124 | School 3 n = 201 | School 4 n = 133 | Aggregate N = 602 |
Difference between schools (p) |
|---|---|---|---|---|---|---|
| Male | 47.9% | 49.2% | 48.3% | 47.4% | 48.2% | 0.99 |
| Age, mean (SD) | 15.41 (0.3) | 15.39 (0.3) | 15.41 (0.3) | 15.5 (0.3) | 15.4 (0.3) | <0.001 |
| White ethnicity | 86.8% | 96.0% | 87.6% | 82.7% | 88.0% | <0.001 |
| Family affluence, mean (SD) | 2.19 (0.7) | 2.08 (0.7) | 2.49 (0.6) | 2.25 (0.7) | 2.3 (0.7) | <0.001 |
| Disruptive behaviour disorders | ||||||
| Oppositional defiant disorder (ODD) | <1% | 4.8% | 2.5% | 5.3% | 3.2% | 0.11 |
| Conduct disorder (CD) | 4.2% | <1% | 1.5% | 6.7% | 3.2% | <0.05 |
| Attention deficit hyperactive disorder (ADHD) | <1% | 0% | 0% | 3.7% | 1.0% | <0.01 |
| Anxiety disorders | ||||||
| Social phobia | 7.6% | 4.0% | 1.5% | 3.8% | 4.0% | 0.05 |
| Separation anxiety | 5.6% | 3.2% | 1.0% | 6.7% | 3.8% | <0.05 |
| Specific phobia | 9.0% | 4.0% | 4.5% | 9.0% | 6.5% | 0.18 |
| Panic attacks | 0% | <1% | <1% | 1.5% | <1% | 0.49 |
| Agoraphobia | 5.6% | 4.8% | <1% | 2.2% | 3.0% | <0.05 |
| Generalized anxiety | 0% | <1% | <1% | 1.5% | <1% | 0.49 |
| Selective mutism | <1% | <1% | <1% | 0% | <1% | 0.80 |
| Obsessive compulsive disorder (OCD) | 2.8% | 6.5% | 5.9% | 5.3% | 5.1% | 0.45 |
| Post traumatic stress disorder (PTSD) | 0% | <1% | 0% | <1% | 0.3% | 0.46 |
| Binary disruptive behaviour variable | 5.6% | 5.7% | 4.0% | 14.3% | 8.1% | <0.01 |
| Binary anxiety variable | 23.6% | 15.3% | 10.9% | 15.8% | 18.5% | 0.03 |
| Friendship indegree, mean (SD) | 2.8 (2.1) | 3.7 (2.4) | 4.2 (2.7) | 4.3 (2.6) | 3.8 (2.5) | <0.001 |
| Friendship outdegree | 2.8 (1.6) | 3.8 (1.7) | 4.1 (1.6) | 4.4 (1.7) | 3.8 (1.8) | <0.001 |
Note. N = 602.
Between school differences were tested with chi-square tests for categorical variables, and one-way ANOVAs for continuous variables.