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WAEC Mathematics 2000 Question 20

Question 20

Measures of Dispersion

Calculate the standard deviation of the following marks: 2, 3, 6, 2, 5, 0, 4, 2.

  1. A.1.5
  2. B.1.7
  3. C.1.8
  4. D.1.9.
Show the answer and explanation

Answer: C (1.8)

Explanation

Mean = 24/8 = 3. Squared deviations add to 1 + 0 + 9 + 1 + 4 + 9 + 1 + 1 = 26. Variance = 26/8 = 3.25, so SD ≈ 1.8.