Table 1.
Means and SDs for all model variables by TCPy quartile groups
| Lowest 25% | 25–50% | 50–75% | Highest 25% | Full Sample | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model Variables | Mean | SD | Mean | SD | Mean | SD | Mean | SD | Mean | SD |
| Average TCPy (μg /g creatinine) | 9.25 | 2.15 | 14.90 | 1.47 | 21.48 | 2.25 | 49.87 | 44.22 | 24.00 | 27.20 |
| Cognitive Latent Variable | .09 | .36 | .03 | .41 | .01 | .36 | −.13 | .42 | .00 | .40 |
| BVRT | .06 | .93 | −.01 | 1.04 | .03 | .97 | −.11 | 1.03 | −.01 | 1.00 |
| DPrime | .19 | .91 | −.19 | 1.00 | .03 | 1.06 | .01 | .97 | .00 | 1.00 |
| DST Forward | .29 | 1.13 | −.06 | .97 | −.11 | .96 | −.09 | .89 | .00 | 1.00 |
| DST Reverse | .36 | 1.10 | −.05 | 1.00 | −.11 | .92 | −.15 | .90 | .00 | 1.00 |
| MTS Correct Count | .21 | 1.06 | −.06 | .94 | −.09 | .98 | −.06 | .98 | .00 | 1.00 |
| SDL | .17 | .81 | .10 | .91 | −.03 | 1.02 | −.24 | 1.16 | .00 | 1.00 |
| SDT Latency | .17 | .98 | .10 | .99 | .04 | .84 | −.29 | 1.09 | .01 | .99 |
| Similarities | .03 | .96 | .12 | 1.05 | .00 | .94 | −.20 | 1.01 | −.01 | 1.00 |
| VMI | .16 | .88 | −.02 | 1.07 | .02 | .99 | −.15 | 1.02 | .00 | 1.00 |
| Trails A | .09 | .80 | .09 | .88 | .11 | .89 | −.30 | 1.26 | .00 | .99 |
| Trails B | .07 | .96 | .00 | 1.03 | .14 | .89 | −.24 | 1.07 | .00 | 1.00 |
| Motor Latent Variable | .12 | .40 | .01 | .43 | −.01 | .41 | −.12 | .41 | .00 | .43 |
| SAP Right | .08 | 1.08 | .00 | .87 | −.03 | .99 | −.06 | 1.04 | −.01 | .99 |
| SAP Left | .17 | 1.13 | −.03 | .93 | −.07 | .91 | −.06 | .98 | −.01 | .99 |
| SRT Timely Latency | .22 | 1.06 | −.03 | .97 | −.07 | .98 | −.07 | .98 | .00 | 1.00 |
| Tapping, Alternating | .35 | .96 | .04 | .87 | −.11 | .93 | −.26 | 1.13 | −.01 | 1.00 |
| Tapping, Left | .19 | .94 | −.05 | .92 | .02 | 1.18 | −.16 | .87 | −.01 | 1.00 |
| Tapping, Right | .23 | .99 | −.02 | 1.00 | −.07 | 1.10 | −.13 | .84 | −.01 | 1.00 |
| Covariates | ||||||||||
| Age | 18.52 | 2.82 | 17.09 | 2.18 | 17.04 | 2.69 | 17.36 | 2.48 | 17.50 | 2.60 |
| Education | 11.61 | 1.90 | 11.08 | 2.16 | 10.62 | 2.29 | 10.69 | 2.12 | 11.00 | 2.15 |
| Parent Education | 11.17 | 3.82 | 11.13 | 4.20 | 10.72 | 3.87 | 10.59 | 4.45 | 10.90 | 4.08 |
| Income, Subjective | 2.31 | .90 | 2.28 | .86 | 2.23 | .92 | 2.39 | .92 | 2.30 | .90 |
| Income, Items | 11.66 | 1.35 | 11.87 | 1.67 | 11.67 | 1.67 | 11.95 | 1.77 | 11.79 | 1.62 |
| Group | N = 19, 40 | N = 18, 43 | N = 18, 43 | N = 10, 51 | N = 65, 177 | |||||
| Field Station | ||||||||||
| Quesna | N = 22 | N = 20 | N = 12 | N = 14 | N = 68 | |||||
| Alshohadaa | N = 10 | N = 21 | N = 25 | N = 14 | N = 70 | |||||
| Tala | N = 14 | N = 12 | N = 10 | N = 18 | N = 54 | |||||
| Berket El Sabe | N = 13 | N = 8 | N = 14 | N = 15 | N = 50 | |||||
Note. Neurobehavioral tasks are z-scored, with higher values indicating better performance. Latent variables are standardized with higher values indicating better performance. SD = standard deviation; BVRT = Benton visual retention task; DST = digit span task; MTS = match to sample; SAP = santa ana pegboard; SDL = serial digit learning; SDT = symbol digit task; SRT = simple reaction time; VMI = visual motor integration. Education is presented in years. Subjective income is rated on a 4-point scale from inadequate to enough money to save. Income based on items is a possible of 19 items the family may own, with higher scores indicating better income standing. Group is presented as non-applicators, applicators.