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JAMB Mathematics 1992 Question 45

Question 45

Measures of Dispersion

If the scores of 3 students in a test are 5, 6 and 7, find the standard deviation of their scores.

  1. A.2/3
  2. B.2/(3√3)
  3. C.√(2/3)
  4. D.√3/2
Show the answer and explanation

Answer: C (√(2/3))

Explanation

The mean is 6, and the squared deviations are 1, 0 and 1. Variance = 2/3, so the standard deviation is √(2/3).