Table 7.
Distribution of NOx predictions with low or high shared Multiplicative Exposure Measurement Error (SMME) across season or time period drawn from a random sample of 2500 predictions from the city of Long Beach, California.
| Low SMME (Covariance < 80th percentile) na (%) |
High SMME (Covariance ≥ 80th percentile) na (%) |
p-Valueb | |
|---|---|---|---|
| Seasonc | |||
| Spring | 542 (27.5) | 76 (15.0) | – |
| Winter | 403 (20.4) | 193 (39.2) | < 0.001 |
| Summer | 568 (28.9) | 47 (9.5) | < 0.001 |
| Fall | 454 (23.1) | 176 (35.8) | < 0.001 |
| Time period | |||
| 1992–2000 | 576 (29.3) | 214 (43.4) | – |
| 2001–2004 | 579 (29.5) | 139 (28.2) | < 0.001 |
| 2005–2012 | 812 (41.3) | 139 (28.2) | < 0.001 |
a
Total sample n = 2459 after accounting for repeat predictions within sample.
b
Welch non-parametric two sided t-test.
c
Seasons defined as winter (December through February), spring (March through May), summer (June through August), fall (September through November).