Biostatistics & Research · single question
When does the prevalence measure of cancer apply to 'cases of cancer in the USA from 2010 until today'?
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Correct answer: C. Prevalence
PREVALENCE measures ALL EXISTING CASES of a condition in a population at a given point in time or over a specified period. 'Cases of cancer in the USA from 2010 until today' describes all existing cases over a time period = PERIOD PREVALENCE. INCIDENCE measures only NEW cases occurring in a defined period. Since this includes all cases existing from 2010 to the present (not just new ones), it is prevalence.
- A. INCORRECT. Incidence measures only NEW cases occurring in a specific time period — it does not count existing cases from previous years.
- B. INCORRECT. Range describes the spread of data values — not a measure of disease occurrence.
- C. CORRECT. Period prevalence counts ALL existing cases over a defined time period (2010 to today). This includes cases diagnosed before 2010 that are still present, as well as new cases diagnosed during the period.
- D. INCORRECT. Mean (average) is a statistical measure of central tendency — not a measure of disease frequency.
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