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Biostatistics & Research · single question

Which of the following best defines PREVALENCE?

  1. Number of existing cases of a disease in a population at a given point in time
  2. The proportion of truly positive cases correctly identified by a test
  3. The proportion of truly negative cases correctly identified by a test
  4. Number of new cases of a disease in a population over a time period
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Correct answer: A. Number of existing cases of a disease in a population at a given point in time

  • A. Prevalence = (existing cases ÷ total population) × 100. It measures the PROPORTION of a population with a disease at a specific time, including both old and new cases.
  • B. This describes SENSITIVITY.
  • C. This describes SPECIFICITY.
  • D. This describes INCIDENCE — the rate of new cases appearing over a defined time period.

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