| Samples (n) | ± SD (OD units) |
---|---|---|
May, 2003 | 35 | 1.240 ± 0.350 |
June, 2003 | 74 | 1.087 ± 0.284 |
July, 2003 | 172 | 1.203 ± 0.306 |
Aug., 2003 | 152 | 1.061 ± 0.376 |
Sept., 2003 | 123 | 1.105 ± 0.378 |
Oct., 2003 | 35 | 1.097 ± 0.282 |
Nov., 2003 | 77 | 0.835 ± 0.327†‡§¶* |
Dec., 2003 | 35 | 0.829 ± 0.232†§* |
Jan.–Feb., 2004 | 67 | 0.737 ± 0.169†‡§¶*# |
Mar–Apr, 2004 | 34 | 0.678 ± 0.179†‡§¶*# |
May–June, 2004 | 46 | 0.621 ± 0.181†‡§¶*# |
F value | Â | 30.62 |
p value | Â | 0.0000 |