P89StatisticsIntermediateCalculate8 min
Calculate the Expected Number of False Positives
Calculate expected false alarms from case volume, negative prevalence, and a false-positive rate.
#calculate#false positives#probability
Scenario
A screening system evaluates 50,000 cases. About 96% are truly negative, and the false-positive rate is 1.5% among truly negative cases.
Problem statement
Calculate the expected number of false positives and interpret it operationally.
Your Task
- Calculate the number of truly negative cases.
- Apply the false-positive rate.
- Explain why expected is not a guaranteed observed count.
Related Concepts
Expected valueFalse-positive rateBase rates
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