Antibody titres against dengue virus in a sample range from 1:2 to 1:5120, producing extreme positive skew. Which measure of central tendency is most suitable for summarising these titres?
- A Arithmetic mean
- B Geometric mean ✓
- C Median
- D Harmonic mean
Correct answer: B. Geometric mean
Explanation
The geometric mean, the nth root of the product of n observations, is preferred for data that span several orders of magnitude with positive skew, such as antibody titres, bacterial colony counts and dilution-based serological measurements. Titres are conventionally analysed after log transformation, and the geometric mean is the antilog of the mean of log-transformed values. The arithmetic mean would be dragged upward by high titres, while the median discards magnitude information.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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