Table III.
Results of Multiple Regression Analyses
| Group effects (CON>FASD) (Site and Age regressed out) | Group effects (CON>FASD) (Site, Age, and ICV regressed out) | PFL (FASD group) (Site, Age, Sex, and ICV regressed out) | Lipometer (FASD group) (Site, Age, Sex, and ICV regressed out) | FSIQ (FASD group) (Site, Age, Sex, and ICV regressed out) | |
|---|---|---|---|---|---|
| LEFT HEMISPHERE | |||||
| Total white matter volume |
*F-ratio = 20.416 p < 0.001 |
F-ratio = 2.494 p = 0.118 |
|||
| Total cortical gray matter |
F-ratio = 21.622 p < 0.001 |
F-ratio = 4.253 p = 0.042 |
|||
| Thalamus |
F-ratio = 19.508 p < 0.001 |
F-ratio = 3.114 p = 0.081 |
F-ratio = 2.448 p = 0.125 |
F-ratio = 5.691 p = 0.021 |
|
| Ventral diencephalon |
F-ratio = 18.865 p < 0.001 |
F-ratio = 3.330 p = 0.071 |
F-ratio = 5.485 p = 0.024 |
F-ratio = 1.722 p = 0.196 |
|
| Caudate |
F-ratio = 12.144 p = 0.001 |
F-ratio = 1.631 p = 0.205 |
F-ratio = 0.023 p = 0.881 |
F-ratio = 0.278 p = 0.600 |
F-ratio = 2.809 p = 0.100 |
| Putamen |
F-ratio = 20.513 p < 0.001 |
F-ratio = 4.901 p = 0.029 |
F-ratio = 0.505 p = 0.481 |
F-ratio = 2.613 p = 0.113 |
F-ratio = 5.316 p = 0.025 |
| Pallidum |
F-ratio = 18.125 p < 0.001 |
F-ratio = 3.859 p = 0.052 |
F-ratio = 6.780 p = 0.012 |
||
| Hippocampus |
F-ratio = 13.113 p < 0.001 |
F-ratio = 1.155 p = 0.285 |
|||
| Amygdala |
F-ratio = 5.812 p = 0.018 |
F-ratio = 0.015 p = 0.904 |
|||
| RIGHT HEMISPHERE | |||||
| Total white matter volume |
F-ratio = 19.535 p < 0.001 |
F-ratio = 1.997 p = 0.161 |
|||
| Total cortical gray matter |
F-ratio = 21.754 p < 0.001 |
F-ratio = 4.219 p = 0.043 |
|||
| Thalamus |
F-ratio = 17.782 p < 0.001 |
F-ratio = 2.578 p = 0.112 |
F-ratio = 4.445 p = 0.041 |
||
| Ventral Diencephalon |
F-ratio = 16.694 p < 0.001 |
F-ratio = 2.478 p = 0.119 |
F-ratio = 4.878 p = 0.032 |
||
| Caudate |
F-ratio = 14.049 p < 0.001 |
F-ratio = 2.653 p = 0.107 |
F-ratio = 0.140 p = 0.710 |
F-ratio = 0.095 p = 0.760 |
F-ratio = 2.255 p = 0.140 |
| Putamen |
F-ratio = 16.204 p < 0.001 |
F-ratio = 2.819 p = 0.097 |
F-ratio = 3.995 p = 0.052 |
F-ratio = 7.805 p = 0.007 |
|
| Pallidum |
F-ratio = 18.673 p < 0.001 |
F-ratio = 4.371 p = 0.039 |
F-ratio = 2.754 p = 0.104 |
F-ratio = 1.287 p = 0.263 |
|
| Hippocampus |
F-ratio = 14.855 p < 0.001 |
F-ratio = 1.546 p = 0.217 |
|||
| Amygdala |
F-ratio = 6.128 p = 0.015 |
F-ratio = 0.031 p = 0.860 |
|||
*
In multiple regressions, F-ratio is used to test the hypothesis that the slopes of the regression lines are 0. The F is large when the independent variable helps to explain the variation in the dependent variable, independently of the other explanatory variables that are regressed out. For instance, here we reject the hypothesis that the slope of the regression line is 0 (F-ratio = 20.416, p < 0.001), meaning that there is a significant linear relation between total white matter volume and group, independent of age and site. Bold font represents significant results (p < 0.05), italicized numbers represent results significant at trend-level (0.05 < p < 0.1).