6, 7, 10, 12, 13, 4, 8, 12
Mean \(\bar{x}=\frac{\sum_{i=1}^{8}}{n}=\frac{6+7+10+12+13+4+8+12}{8}=\frac{72}{8}=9\)
The following table is obtained
| \(x_i\) | \((x_i-\bar{x})\) | \((x_i-\bar{x})^2\) |
| 6 | 3 | 9 |
| 7 | 2 | 4 |
| 10 | 1 | 1 |
| 12 | 3 | 9 |
| 13 | 4 | 16 |
| 4 | 5 | 25 |
| 8 | 1 | 1 |
| 12 | 3 | 9 |
| 74 |
\(Variance(σ^2)=\frac{1}{n}\sum_{i=1}^{8}(x_i-\bar{x})^2=\frac{1}{8}×74=9.25\)