Find the variance of 1, 2, 0, -3, 5, -2, 4.
FURTHER MATHEMATICS
WAEC 2014
Find the variance of 1, 2, 0, -3, 5, -2, 4.
- A. \(\frac{52}{7}\)
- B. \(\frac{40}{7}\)
- C. \(\frac{32}{7}\)
- D. \(\frac{27}{7}\)
Correct Answer: A. \(\frac{52}{7}\)
Explanation
Mean, \(\bar{x} = \frac{1+2+0+(-3)+5+(-2)+4}{7} = \frac{7}{7} = 1\)
| \(x\) | \((x - \bar{x})\) | \((x - \bar{x})^{2}\) |
| 1 | 0 | 0 |
| 2 | 1 | 1 |
| 0 | -1 | 1 |
| -3 | -4 | 16 |
| 5 | 4 | 16 |
| -2 | -3 | 9 |
| 4 | 3 | 9 |
| Total (n) = 7 | 52 |
Variance = \(\frac{\sum (x - \bar{x)^{2}}{n}\)
= \(\frac{52}{7}\)
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