Table 2.
Numerical summaries of values for the variables used in the analysis, per county
| Mean | Median | IQR | Min | Max | |
|---|---|---|---|---|---|
| Population size | 4,544 | 2,558 | 3,636 | 181 | 52,056 |
| Percent black | 20.50 | 17.80 | 27.50 | 0.20 | 62.50 |
| Percent Hispanic | 6.40 | 5.50 | 4.80 | 1.30 | 20.60 |
| Percent extremely low birth weight | 9.40 | 9.50 | 2.60 | 4.30 | 19.60 |
| Percent using well water | 34.30 | 28.90 | 33.30 | 1.20 | 88.10 |
| Percentage in poverty | 19.20 | 18.50 | 6.20 | 9.20 | 31.50 |
| Number of doctors | 303 | 243 | 259 | 0 | 2,274 |
| Percent with speech/language disorder | 1.69 | 1.61 | 1.44 | 0.16 | 5.95 |
| Percent with delayed milestones | 0.24 | 0.03 | 0.25 | 0.00 | 1.97 |
| Percent with hearing loss | 0.026 | 0 | 0.056 | 0.00 | 0.289 |
| * Manganese (μg/L) | 71.50 | 54.44 | 52.94 | 18.70 | 406.35 |
| * Arsenic (μg/L) | 1.15 | 0.68 | 0.59 | 0.50 | 9.32 |
| * Lead (μg/L) | 284.03 | 139.23 | 261.66 | 2.77 | 4,357.94 |
*
Metal concentrations represent the mean and median of the 99 county means, and medians, IQR: Interquartile range