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Question
Find the mean and variance for the data.
6, 7, 10, 12, 13, 4, 8, 12
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Solution
Mean `overlinex = (sumx_i)/n`
= `(6 + 7 + 10 + 12 + 13 + 4 + 8 + 12)/8`
= `72/8`
= 9
| xi | `x_i - overline x` | `(x_i - overline 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 = `(sum (x_i - overline x)^2)/n`
= `74/8`
= 9.25
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