Table 2.

Confidence interval (95%) for means of incidence of histologic features

	Lower bound	Upper bound
Focal thickening	1.21	1.59
Vascular congestion	1.54	2.06
Alveolar edema	1.06	1.94
Alveolar hemorrhage	1.61	2.34
Interstitial neutrophil infiltration	1.46	2.44
Intraalveolar neutrophil infiltration	0.26	1.34