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WAEC Further Mathematics 2007 Question 37

Question 37

Statistics

Calculate, correct to one decimal place, the standard deviation of the numbers −1, 5, 0, 2 and 9.

  1. A.7.2
  2. B.6.6
  3. C.3.6
  4. D.3.2
Show the answer and explanation

Answer: C (3.6)

Explanation

Mean = 15/5 = 3. Squared deviations 16, 4, 9, 1, 36 sum to 66, so SD = √(66/5) = √13.2 ≈ 3.6.