Fig. 3

Results of 10,000 sparrpowR iterations simulating 18 cases and 982 controls assuming multivariate normal distributions with standard deviations of 0.83 and 1.67 km, respectively. (Left) The first iteration of simulated data. Simulated case locations are red-colored dots and simulated control locations are blue-colored dots. (Right) The green-colored area is sufficiently powered to detect a spatial cluster of cases relative to controls. The blue-colored area is insufficiently powered to detect a spatial cluster of cases relative to controls. The identified concentrated animal feeding operation (CAFO) is signified by the black “X” and the base map is of Fort Dodge, Iowa. The blue lines represent regions with radii of 5 and 10 km from the identified CAFO