A researcher measures serum creatinine (mean 1.2 mg/dL, SD 0.3) and blood urea nitrogen (mean 14 mg/dL, SD 4) in the same subjects. To compare the relative variability of these two measurements, which statistic should be used?
- A Standard deviation
- B Standard error of the mean
- C Coefficient of variation ✓
- D Variance
Correct answer: C. Coefficient of variation
Explanation
The coefficient of variation (CV = SD/mean x 100) expresses variability relative to the mean, allowing comparison of dispersion between measurements with different units or vastly different means. Standard deviation and variance are absolute measures and cannot directly compare variability across different scales. Standard error measures precision of the mean estimate, not variability of observations.
Reference: B K Mahajan's Methods in Biostatistics, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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