The coefficient of variation for a glucose concentration range of 80-100 mg/dL is which value?

The coefficient of variation for a glucose concentration range of 80-100 mg/dL is which value?

• A. 3.5
• B. 5.562
• C. 5.0
• D. 6.2

Answer: (B)

The measurement uses a range-based estimate of variability. When you only know the min and max, you can approximate the standard deviation as one-fourth of the range, and then express the coefficient of variation as (SD / mean) × 100%. Compute the range: 100 − 80 = 20 mg/dL. The mean: (80 + 100) / 2 = 90 mg/dL. Estimated SD ≈ 20 / 4 = 5 mg/dL. The CV ≈ (5 / 90) × 100% ≈ 5.56%. So the coefficient of variation is about 5.56%.

The measurement uses a range-based estimate of variability. When you only know the min and max, you can approximate the standard deviation as one-fourth of the range, and then express the coefficient of variation as (SD / mean) × 100%.

Compute the range: 100 − 80 = 20 mg/dL. The mean: (80 + 100) / 2 = 90 mg/dL. Estimated SD ≈ 20 / 4 = 5 mg/dL. The CV ≈ (5 / 90) × 100% ≈ 5.56%.

So the coefficient of variation is about 5.56%.