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WAEC Mathematics 2020 Question 35

Question 35

Measures of Dispersion

The mean of the numbers 15, 21, 17, 26, 18 and 29 is 21. Calculate the standard deviation.

  1. A.9
  2. B.6
  3. C.5
  4. D.0
Show the answer and explanation

Answer: C (5)

Explanation

Squared deviations from 21: 36, 0, 16, 25, 9, 64, total 150. Variance = 150/6 = 25, so the standard deviation is 5.