Coefficient of Variation

The variance and the standard deviation are useful as measures of variation of the values of a single variable for a single population (or sample).

 If we want to compare the variation of two variables we cannot use the variance or the standard deviation because:

1.   The variables might have different units.

2.   The variables might have different means.

We need a measure of the relative variation  that will not depend on either the units or on how large the values are. This measure is the coefficient of variation (C.V.) which is defined by:

Coefficient of Variation refers to the statistical measure which helps in measuring the dispersion of the various data points in the data series around mean and is calculated by dividing the standard deviation by mean and multiplying the resultant with 100.

Step 1: Find the mean.

Step 2. Subtract the mean from each score.

Step 3: Take the square of the difference.

Step 4: Compute for the standard deviation.

Step 4: Use the formula.