Every 13 or 17 years a brood of cicadas, sometimes in Biblical proportions, emerges from underground in the northeastern part of the United States. Although harmless to humans, cicadas cause damage to...

Every 13 or 17 years a brood of cicadas, sometimes in Biblical proportions, emerges from underground in the northeastern part of the United States. Although harmless to humans, cicadas cause damage to small trees and shrubs, and they make a piercing, irritating sound. Some research suggests that the density of cicadas is related to the density of moles, natural predators of cicada. Plots were randomly selected, and the density of moles per acre (x) and the density of cicadas per acre (y, in millions) were carefully estimated. The data are given in the following table.