TABLE 3.
Descriptive Statistics of the Time-Varying Variables
| N | % | Mean | SD | Range | |
|---|---|---|---|---|---|
| Age: | |||||
| 2 | 374,737 | 39.3 | |||
| 3 | 321,633 | 33.7 | |||
| 4 | 158,724 | 16.6 | |||
| 5 | 69,334 | 7.3 | |||
| 6 | 29,194 | 3.1 | |||
| Distance to the nearest child with autism in year t − 1: | |||||
| 1–200 m | 108,402 | 11.4 | |||
| 201–500 m | 272,107 | 28.5 | |||
| 501 m–1 km | 295,189 | 31.0 | |||
| 1–2 km | 176,053 | 18.5 | |||
| 2–5 km | 63,711 | 6.7 | |||
| Over 5 km | 38,160 | 4.0 | |||
| Distance to the nearest child with autism, in meters | 1,340.4 | 3,842.7 | 1.1 to 154,658.6 | ||
| Logged distance to the nearest child with autism | 6.5 | 11.1 | .1 to 12.0 | ||
| Age 0–9 population density in school district per square mile | 246.5 | 281.1 | .3 to 1421.1 | ||
| Logged age 0–9 population density in school district | 4.8 | 1.5 | −3.5 to 7.3 | ||
| Median household income in school district, in $ | 47,067.6 | 20,267.7 | 1,997.4 to 179,550.2 | ||
Note.—N = 953,622 person-years.