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Coefficient of Dispersion Formula:
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The Coefficient of Dispersion (COD) is a statistical measure that quantifies the relative variability of a dataset. It is calculated as the ratio of the standard deviation to the mean, providing a normalized measure of dispersion that is independent of the unit of measurement.
The calculator uses the COD formula:
Where:
Explanation: The COD expresses the standard deviation as a percentage of the mean, allowing comparison of variability across different datasets with different units or scales.
Details: COD is particularly useful in gas measurement and analysis as it helps quantify the uniformity or heterogeneity of gas distribution, concentration variations, or measurement consistency across different samples or locations.
Tips: Enter the standard deviation and mean values in consistent units. Both values must be positive, with mean greater than zero for valid calculation.
Q1: What does a high COD value indicate?
A: A high COD indicates greater relative variability in the data, suggesting less consistency or greater heterogeneity in gas measurements.
Q2: What is considered a good COD value for gas measurements?
A: Typically, lower COD values (closer to 0) indicate more consistent measurements. Acceptable ranges vary by application, but values below 0.1-0.2 often indicate good uniformity.
Q3: How is COD different from coefficient of variation?
A: COD and coefficient of variation (CV) are essentially the same measure, both representing standard deviation relative to the mean. The terms are often used interchangeably.
Q4: Can COD be used to compare different gases?
A: Yes, since COD is a dimensionless ratio, it can be used to compare variability across different gases or measurement conditions.
Q5: What are limitations of using COD?
A: COD can be sensitive to outliers and may not be appropriate for datasets with means close to zero. It's also less meaningful for non-normal distributions.