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WAEC Mathematics 2017 Question 47

Question 47

Measures of Dispersion

Calculate the variance of 2, 3, 3, 4, 5, 5, 5, 7, 7 and 9.

  1. A.2.2
  2. B.3.4
  3. C.4.0
  4. D.4.2
Show the answer and explanation

Answer: D (4.2)

Explanation

Mean = 50/10 = 5. Squared deviations: 9, 4, 4, 1, 0, 0, 0, 4, 4, 16, total 42. Variance = 42/10 = 4.2.