Figure 3

Choropleth maps with numerator/denominator cumulative frequency legends. A quantile classification in which an equal number of towns are in each data class is used to portray the spatial distribution of the percent of low birthweight births by town in Connecticut in the upper-left diagram and to portray the spatial distribution of Lyme disease per 100,000 population by town in Connecticut in the upper-right diagram. A numerator/denominator cumulative frequency legend associated with each map is presented beneath the respective map. In these legends, the cumulative frequency curve for numerator is given in blue and that for the denominator is given in green. The grand rate for each health outcome is given by a vertical yellow line that defines the maximum separation between the two curves for any value.