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The seasonal effects in each defined geographical zone on ΔMD, the change in Mean Deviation since the previous visit.
| Zone | Magnitude of seasonal effect (dB) |
Date of peak | Statistical significance of magnitude (p) |
|---|---|---|---|
| Atlantic | 0.04 | 18 Feb | 0.049 |
| Central | 0.11 | 12 Mar | <0.001 |
| North | 0.21 | 1 Feb | <0.001 |
| Pacific Northwest |
0.07 | 29 Apr | 0.005 |
| Southeast | 0.02 | 10 Jul | 0.364 |
| West | 0.07 | 4 Feb | <0.001 |
