A new screening blood test for a cancer has a sensitivity of 90% and a specificity of 95%. It is proposed for use in the general population aged 50–74, in whom the prevalence of the cancer is 1%. A 58-year-old woman with no symptoms has a positive result and asks what this means.
Of every 100 people in this population who test positive, approximately how many actually have the cancer?
Keep going with ten more like this one.
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