PSYC 3850 Lecture : Chapter 3
9 Feb 2012
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Document Summary
Rate is defined as the ratio of all persons who have a given disorder to the total number of persons in a given population. The number of cases has to be expressed with reference to some comparison number (often 1000) Prevalence and incidence have clearly defined meanings, however they are often misapplied in the literature. Used when we wish to know something about the overall numbers that are present in the population at a given time. Prevalence rates are given relative to the total population on which the study is based. Proper meaningful reference population is important : e. g. Tay-sachs disease among ashkenazi jews (vs. randomly selected population) Key point: importance of being an informed consumer of epidemiological information. Used to know something about the number of new cases that arise in a given span of time. 60 new cases of down syndrome from 1981 to 1984 in a population of.
