Overview
Variance measures the dispersion of a set of data points around their mean. It is calculated by taking the average of the squared differences from the mean.
Calculation
- Find the mean.
- Subtract the mean from each value and square the result.
- Find the average of those squared differences.
Interpretation
- Low Variance: Data points are close to the mean.
- High Variance: Data points are spread out over a wide range.
Note
Because variance is in squared units, the Standard Deviation (the square root of variance) is often used for easier interpretation in the original units of the data.