Table 2. Descriptive statistics and comparisons of the values for the LB1 endocast with values for our sample of 6 subjects with Down syndrome.
| Parameter | Number | Mean | Std Dev | Std Err Mean | Lower 95% | Upper 95% | P value* | |
|---|---|---|---|---|---|---|---|---|
| Endocast length (fp-op, mm) | ||||||||
| Down syndrome | 6 | 154.75 | 6.8 | 2.78 | 147.61 | 161.89 | 0.002 | |
| LB1 | 1 | 118.4 | . | . | . | . | ||
| Cerebellar width (mm) | ||||||||
| Down syndrome | 6 | 100.63 | 3.54 | 1.44 | 96.92 | 104.34 | <.001 | |
| LB1 | 1 | 76.4 | . | . | . | . | ||
| Cerebral width (mm) | ||||||||
| Down syndrome | 6 | 124.95 | 5.76 | 2.3 | 118.91 | 131 | 0.009 | |
| LB1 | 1 | 103.4 | . | . | . | . | ||
| Frontal breadth | ||||||||
| Down syndrome | 6 | 102.28 | 5.06 | 2.07 | 96.97 | 107.6 | 0.005 | |
| LB1 | 1 | 80.1 | . | . | . | |||
| Endocranial volume (cm3) | ||||||||
| Down syndrome | 6 | 1174.17 | 132.35 | 54.03 | 1035.28 | 1313.06 | 0.002 | |
| LB1 | 1 | 417 | . | . | . | . | . | |
Note.―fp-op = frontal pole-occipital pole.
*For each measurement, P is the probability of obtaining a result at least as extreme as that observed if the null hypothesis were true that the value for LB1 is not lower than the mean value for our 6 subjects with DS. After statistical levels of significance were corrected by adjusting for the false discovery rate, the adjusted levels to achieve statistical significance ranged from 0.01 for cerebellar width (mm) to 0.05 for cerebral width (mm), with all P values in Table 2 being below these levels and remaining statistically significant.