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WAEC 2019 · Paper 1 · Q41

Calculate the variance of 2, 4, 7, 8 and 9.

Worked solution (try it first)
  1. The numbers add up to 30, so the mean is 6.
  2. The squared deviations are 16, 4, 1, 4, 9, which add up to 34.
  3. The variance is 345=6.8\frac{34}{5} = 6.8, option B.

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