Table 2.
Descriptive statistics for daily air temperature, daily PM2.5 exposure, and traffic density across mother’s residences (397,698) in Massachusetts between 2000 and 2008.
| Covariate | Mean | Median | SD | Minimum | Maximum | IQR | 25th percentile | 75th percentile | Days of data available |
|---|---|---|---|---|---|---|---|---|---|
| Predicted air temperature (°C) | 11.3 | 11.4 | 5.6 | –12.1 | 35.49 | 8.9 | 6.9 | 15.8 | 3,285 |
| Cumulative traffic density (daily traffic × length) | 1,309 | 702 | 2,076 | 0 | 29,000 | 1,352 | 258 | 1,611 | 3,285 |
| Predicted PM2.5 (μg/m3) | 10.9 | 9.27 | 5.9 | 0.2 | 56.9 | 6.8 | 6.7 | 13.5 | 3,285 |