Antibody titre values after vaccination are recorded as 1:10, 1:20, 1:40, 1:80 and 1:160. Which measure of central tendency is most appropriate for summarising these values?
- A Arithmetic mean
- B Harmonic mean
- C Geometric mean ✓
- D Mode
Correct answer: C. Geometric mean
Explanation
Titres follow a logarithmic progression where each value is a multiple of the previous one. The geometric mean, computed by taking the antilog of the mean of the log-transformed values, is the standard summary for such multiplicative data and is routinely used in serology. The arithmetic mean would be pulled upward by the higher dilutions, while the harmonic mean applies to rates such as speed.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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