3.9% of a secluded island tribe are infected with a certain disease. There is a test for the disease, however the test is not completely accurate. 92% of those who have the disease will test positive. However 4.4% of those who do not have the disease will also test positive (false positives). Use a tree diagram to find the probability that any given person will test positive. Round your answer to three decimal places if necessary.
P[ Person will test positive ] = P[ Person has disease ]*P[ Test is positive | person has disease ] + P[ Person do not has disease ]*P[ Test is positive | person do not has disease ]
P[ Person will test positive ] = 0.039*0.92 + 0.961*0.044
P[ Person will test positive ] = 0.03588 + 0.042284
P[ Person will test positive ] = 0.078164
P[ Person will test positive ] = 7.8%
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