| R2 | Unstandardised | Standardised |  |  | |
---|---|---|---|---|---|---|
 |  | Beta | Standard error | Beta | t | p-value |
Constant | - | 0.55 | 0.33 | - | 1.70 | 0.09 |
Smoking in pregnancy | 0.04 | 0.21 | 0.06 | 0.18 | 3.34 | 0.001 |
Social class | 0.02 | 0.07 | 0.04 | 0.09 | 1.72 | 0.09 |
Birth weight | 0.007 | -0.0004 | 0.001 | -0.10 | -1.89 | 0.06 |
Gender | 0.02 | -0.28 | 0.10 | -0.15 | -2.84 | 0.005 |
Verbal IQ | 0.02 | -0.004 | 0.003 | -0.09 | -1.68 | 0.09 |
ADHD symptoms | 0.01 | 0.02 | 0.01 | 0.10 | 1.85 | 0.07 |