Maps of counties with significantly greater prostate cancer mortality rates for black males. The threshold difference Δ0 is expressed either in absolute term (deaths/100,000 habitants) or percentage, depending on the type of statistic used (RD versus RR type). One-tailed tests were conducted at a significance level α = 0.01. White polygons depict non-significant (NS) differences, while hatched areas correspond to missing data. Thicker lines delineate state boundaries. The pointing arrows in the right maps indicate the two counties (Alamance, NC: FIPS 37001, Jefferson, AL: FIPS 1073) with the smallest p-value for the one-tailed tests.