WAEC - Mathematics (2000 - No. 20)
Calculate the standard deviation of the following marks; 2, 3, 6, 2, 5, 0, 4, 2
1.5
1.7
1.8
1.9
Explanation
| x | 2 | 3 | 6 | 2 | 5 | 0 | 4 | 2 | 24 |
| x - \(\bar{x}\) | -1 | 0 | 3 | -1 | 2 | -3 | 1 | -1 | |
| \((x - \bar{x})^2\) | 1 | 0 | 9 | 1 | 4 | 9 | 1 | 1 | 26 |
Mean = \(\frac{24}{8} = 3\)
Standard deviation = \(\sqrt{\frac{26}{8}}\)
= \(\sqrt{3.25}\)
= 1.802 \(\approx\) 1.8
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