Which measure of central tendency is most appropriate for summarising serial antibody titre values such as 1:20, 1:40, 1:80 and 1:160?
- A Arithmetic mean
- B Median
- C Geometric mean ✓
- D Mode
Correct answer: C. Geometric mean
Explanation
Titres form a logarithmic progression where each value is a fixed multiple of the previous one. The geometric mean, the antilog of the arithmetic mean of log-transformed values, correctly averages such multiplicative data and is the standard summary for antibody titres in serological surveys. The arithmetic mean is pulled upward by higher dilutions and misrepresents the central value.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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