Figure 6.2 Natural Frequency Tree Diagram for Cancer Problem in Eddy (1982) This tree diagram visually illustrates the solution steps necessary to solve Eddy’s (1982) cancer problem by converting all of the relevant probability information to natural frequencies as suggested by Gigerenzer (2002). Remember, the probability that a person has a disease given a positive screening test result for that disease is the percentage of positive test results that are true positives.
(Source: Gerd Gigerenzer, Director of Max Planck Institute for Human Development, Berlin.)