Figure 13. AIDS Location Quotients and Poisson Probability: North Carolina, 1990

These two maps describe aspects of the spread of AIDS in North Carolina. The top map uses location quotients, or a ratio of proportions, to illustrate the relative incidence of AIDS by county. A location quotient greater than 1 indicates the county has more than its share of cases based on population. The bottom map uses a Poisson distribution to identify counties where incidence is higher than would be expected to occur by chance.

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