A medical screening test for a rare disease has a sensitivity of 95% and a specificity of 90%. In a population where the disease prevalence is 1%, what is the probability that an individual who tests positive actually has the disease (positive predictive value)?
Answer and explanation
Correct answer: A. 8.8% (approximately 9%)
In a sample of 10,000 people: 1% prevalence means 100 have the disease and 9,900 are healthy. Of the 100 diseased, 95% test positive = 95 true positives. Of the 9,900 healthy, 10% test false positive = 990 false positives. Total positive tests = 95 + 990 = 1,085. Positive predictive value (PPV) = true positives / total positives = 95 / 1,085 ≈ 0.0876 (or ~8.8%).
Practise more Electromagnetism, Modern Physics, and Differential Calculus.
Free questions with an explanation for every one, and full timed Toelatingsexamen Arts & Tandarts België (Medical & Dental Entrance Exam) mock tests.
More Electromagnetism, Modern Physics, and Differential Calculus questions
- Two large parallel conducting plates are separated by a distance of 0.020 m in a vacuum. A potential difference of 200 V is applied between…
- A circular wire loop of radius 0.10 m is placed perpendicular to a uniform magnetic field. If the magnetic field decreases uniformly from 0.…
- An ideal electrical transformer has 500 turns on its primary coil and 50 turns on its secondary coil. If an alternating voltage of 240 V is…
- In a photoelectric experiment, monochromatic light with photon energy of 4.5 eV illuminates a clean metal surface having a work function Phi…
- In the Bohr model of the hydrogen atom, the ground-state electron energy is -13.6 eV. What is the energy of the photon emitted when an elect…
- What is the domain of the real-valued function f(x) = sqrt(2x - 6) / (x - 5)?