方差计算器 — 公式
## How to Calculate Variance
### Formula (Population Variance)
**σ² = Σ(xᵢ - μ)² / N**
### Steps
1. Find the mean (μ)
2. Subtract the mean from each value
3. Square each difference
4. Find the average of the squared differences
Variance is the square of the standard deviation.
### Formula (Population Variance)
**σ² = Σ(xᵢ - μ)² / N**
### Steps
1. Find the mean (μ)
2. Subtract the mean from each value
3. Square each difference
4. Find the average of the squared differences
Variance is the square of the standard deviation.
计算示例
Find the variance of 4, 8, and 6.
- Mean = (4 + 8 + 6) / 3 = 6
- Squared differences: (4-6)² = 4, (8-6)² = 4, (6-6)² = 0
- Variance (population) = (4 + 4 + 0) / 3 = 2.6667
- Variance (sample) = (4 + 4 + 0) / 2 = 4