Table 3.
Showing best fit models using a combination of Tanner stage and chronological age variables, with likelihood ratios and differences in AIC. Structures in BOLD show structures where the mixed Tanner stage and age model is a significantly better fit than the Tanner stage only model.
a: Combined model refers to a model incorporating independent effects of Tanner stage and chronological age as well as an interactive Tanner stage by age effect. Interactive model refers to a model using only an interactive Tanner stage by age effect.
b: In females, the best fit model for the putamen was a combined model including independent effects of Tanner stage, linear and quadratic chronological age as well as an interactive Tanner stage by age effect.
* For these structures, a likelihood ratio test is not valid as the models are not nested and have the same number of degrees of freedom. Therefore, significance of the models has been judged using AIC differences. If AIC difference ≥ 5.9, the model is a significantly better fit (equivalent to Akaike weight of < 0.05).
| Structure | Best-fitting Tanner and age modela | Likelihood ratio test compared to Tanner only model | p-value | Difference between AIC |
|---|---|---|---|---|
| Females | ||||
| Amygdala | Combined | 7.67 | 0.006 | |
| Hippocampus | Combined | 23.96 | < 0.0001 | |
| Nucleus accumbens | Interactive | 3.21* | * | 3.21 |
| Caudate | Combined | 14.16 | 0.0002 | |
| Putamen | Combinedb | 28.13 | < 0.0001 | |
| Globus pallidus | Interactive | 3.43* | * | 3.43 |
| Males | ||||
| Amygdala | Combined | 9.48* | * | 9.48 |
| Hippocampus | Combined | 23.06 | < 0.0001 | |
| Nucleus accumbens | Interactive | 4.63 | 0.099 | |
| Caudate | Interactive | 5.29 | 0.071 | |
| Putamen | Combined | 5.16 | 0.023 | |
| Globus pallidus | Interactive | 1.51* | * | 1.51 |