Variance Calculator
Calculate variance (σ² or s²) to measure data spread. Includes both sample and population variance with detailed explanations of the relationship to standard deviation.
Understanding Variance
What is Variance?
Variance measures the average squared deviation from the mean. It quantifies how spread out the data points are. Higher variance means more spread; lower variance means data is clustered near the mean.
When to Use This Calculator
- Statistical analysis requiring variance calculations
- Quality control (measuring process variability)
- Finance (calculating asset volatility)
- Research studies (reporting data dispersion)
Sample vs Population Variance
Sample Variance (s²): Uses n-1 in the denominator (Bessel's correction) to provide an unbiased estimate when working with a sample from a larger population. Population Variance (σ²): Uses n in the denominator when analyzing an entire population.
Common Mistakes
- Using population formula (n) when you should use sample formula (n-1)
- Forgetting to square the deviations before summing
- Comparing variances of data in different units
Educational Purpose Disclaimer
This calculator is provided for educational purposes only. Results should not be used as the sole basis for critical decisions. Always verify important calculations independently and consult qualified professionals when needed.