1. What is %CV?

The coefficient of variation (%CV) is a standardized measure of dispersion of a probability distribution or frequency distribution. It shows the extent of variability in relation to the mean of the population.

2. How Does the Calculator Work?

The calculator uses the %CV formula:

Where:

• \( SD \) — Standard deviation
• \( Mean \) — Mean value

Explanation: The %CV expresses the standard deviation as a percentage of the mean, allowing comparison between datasets with different units or widely different means.

3. Importance of %CV Calculation

Details: %CV is widely used in analytical chemistry, quality control, and laboratory medicine to assess the precision of an assay or measurement method.

4. Using the Calculator

Tips: Enter standard deviation and mean values in the same units. Both values must be positive (mean must be greater than zero).

5. Frequently Asked Questions (FAQ)

Q1: What is a good %CV value?
A: In analytical chemistry, %CV < 5% is generally considered excellent, < 10% is acceptable for most applications, while > 20% is usually unacceptable.

Q2: How is %CV different from standard deviation?
A: Standard deviation is in the units of measurement, while %CV is dimensionless, allowing comparison between different measurement scales.

Q3: When should %CV not be used?
A: %CV should not be used when the mean is close to zero, as it can produce misleadingly high values. It's also less meaningful for interval scales that don't have a true zero.

Q4: Can %CV be negative?
A: No, %CV is always positive since standard deviation is always positive and mean is positive in this calculation.

Q5: How is %CV used in quality control?
A: It's used to monitor the precision of repeated measurements over time, with control limits often set based on historical %CV values.