Table 1. . Summary statistics for 28 continuous HCP attributes used in the modeling analysis.
| Measured quantity | Sample size | Mean | Median | Skewness | % Mild outliers1 | % Extreme outliers2 | 95% CI for mean | |
|---|---|---|---|---|---|---|---|---|
| Lower | Upper | |||||||
| Age (in years) | 841 | 28.76 | 29.00 | −0.08 | 0.00 | 0.00 | 28.51 | 29.01 |
| Handedness3 [−100, 100] | 841 | 65.36 | 80.00 | −2.18 | 0.10 | 0.07 | 62.33 | 68.40 |
| Total household income (binned; 5 ∼ $40,000–49,999) | 836 | 5.01 | 5.00 | −0.28 | 0.00 | 0.00 | 4.87 | 5.16 |
| Years of education completed | 840 | 14.92 | 16.00 | −0.74 | 0.00 | 0.00 | 14.80 | 15.04 |
| Body mass index | 840 | 26.51 | 25.42 | 0.95 | 0.03 | 0.00 | 26.15 | 26.86 |
| Mean hematocrit sample | 740 | 43.39 | 43.50 | −0.68 | 0.02 | 0.00 | 43.05 | 43.73 |
| Diastolic blood pressure | 830 | 76.77 | 76.00 | 0.33 | 0.02 | 0.00 | 76.06 | 77.49 |
| Systolic blood pressure | 830 | 123.76 | 123.00 | 0.51 | 0.01 | 0.00 | 122.80 | 124.71 |
| Systolic-diastolic blood pressure ratio | 830 | 1.63 | 1.61 | 0.97 | 0.03 | 0.00 | 1.61 | 1.64 |
| Hemoglobin A1C | 566 | 5.26 | 5.30 | 0.12 | 0.05 | 0.01 | 5.22 | 5.29 |
| Pittsburgh Sleep Quality Index | 841 | 5.18 | 5.00 | 0.91 | 0.01 | 0.00 | 4.98 | 5.39 |
| NIH Picture Sequence Memory Test | 840 | 111.83 | 110.70 | 0.11 | 0.00 | 0.00 | 110.92 | 112.73 |
| NIH Dimensional Change Card Sort Test | 839 | 115.28 | 115.07 | 0.18 | 0.02 | 0.00 | 114.59 | 115.97 |
| NIH Flanker Inhibitory Control and Attention Test | 841 | 112.52 | 112.21 | 0.25 | 0.01 | 0.00 | 111.84 | 113.20 |
| Penn Progressive Matrices: Number of correct responses | 838 | 16.76 | 18.00 | −0.55 | 0.00 | 0.00 | 16.44 | 17.09 |
| Penn Progressive Matrices: Total skipped items | 838 | 3.12 | 1.00 | 1.01 | 0.00 | 0.00 | 2.86 | 3.39 |
| Penn Progressive Matrices: Median reaction time for correct responses (sec) | 838 | 15.61 | 14.65 | 0.91 | 0.01 | 0.00 | 14.99 | 16.23 |
| NIH Oral Reading Recognition Test | 841 | 116.96 | 117.59 | −0.14 | 0.01 | 0.00 | 116.24 | 117.67 |
| NIH Picture Vocabulary Test | 841 | 116.76 | 117.03 | 0.09 | 0.01 | 0.00 | 116.12 | 117.40 |
| NIH Toolbox Pattern Comparison Processing Speed Test | 841 | 114.15 | 113.16 | 0.22 | 0.03 | 0.00 | 113.14 | 115.16 |
| Delay Discounting: Area under the curve for discounting of $200 | 838 | 0.25 | 0.20 | 1.39 | 0.05 | 0.00 | 0.24 | 0.27 |
| Delay Discounting: Area under the curve for discounting of $40,000 | 838 | 0.50 | 0.49 | 0.05 | 0.00 | 0.00 | 0.48 | 0.52 |
| Variable Short Penn Line Orientation: >Total number correct | 838 | 14.80 | 15.00 | −0.23 | 0.00 | 0.00 | 14.51 | 15.10 |
| Variable Short Penn Line Orientation: Median reaction time divided by expected number of clicks for correct (sec) | 838 | 1.15 | 1.10 | 1.31 | 0.03 | 0.00 | 1.13 | 1.17 |
| Variable Short Penn Line Orientation: Total positions off for all trials | 838 | 24.34 | 21.00 | 3.16 | 0.05 | 0.02 | 23.33 | 25.35 |
| Penn Word Memory Test: Total number of correct responses | 838 | 35.64 | 36.00 | −0.82 | 0.01 | 0.00 | 35.44 | 35.84 |
| Penn Word Memory Test: Median reaction time for correct responses (sec) | 838 | 1.56 | 1.51 | 1.85 | 0.03 | 0.01 | 1.54 | 1.58 |
| NIH List Sorting Working Memory Test | 841 | 111.21 | 108.06 | 0.16 | 0.02 | 0.00 | 110.45 | 111.97 |
1Using the interquartile range (IQR: 75th percentile minus 25th percentile), we define a mild outlier to be any point greater than the 75th percentile or less than the 25th percentile by an amount at least 1.5 times the IQR.
2Using the interquartile range (IQR: 75th percentile minus 25th percentile), we define an extreme outlier to be any point greater than the 75th percentile or less than the 25th percentile by an amount at least 3 times the IQR.
3Handedness is a bimodal distribution with a strong preference for right-handedness in the HCP cohort, thus labeling as extreme outliers a large number of individuals with strong left-hand dominance.