Is RSD the same as CV?
The most commonly used estimates of precision are the standard deviation (SD) and the relative standard deviation (RSD). RSD also is known as the coefficient of variation (CV).
How is SD different from CV?
The coefficient of variation is simply the standard deviation divided by the mean. The CV lets you compare the amount of dispersion in two distributions that are on different scales. The SD of SAT will be much higher, simply because the range is so much bigger. The CV accounts for this.
Can you have a negative variance?
A variance value of zero, though, indicates that all values within a set of numbers are identical. Every variance that isn’t zero is a positive number. A variance cannot be negative. That’s because it’s mathematically impossible since you can’t have a negative value resulting from a square.
What happens when variance is negative?
Negative Variance Means You Have Made an Error As a result of its calculation and mathematical meaning, variance can never be negative, because it is the average squared deviation from the mean and: Anything squared is never negative. Average of non-negative numbers can’t be negative either.