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WAEC Further Mathematics 2011 Question 27

Question 27

Statistics

Find the standard deviation of the numbers 3, 6, 2, 1, 7 and 5.

  1. A.2.00
  2. B.2.16
  3. C.2.50
  4. D.2.56
Show the answer and explanation

Answer: B (2.16)

Explanation

Mean = 24/6 = 4. Squared deviations: 1, 4, 4, 9, 9, 1, total 28. s.d. = √(28/6) = √4.67 ≈ 2.16.