WAEC Mathematics 2017 Objective — Question 47
Question 47 of 50 from the West African Examinations Council (WAEC) Mathematics 2017 Objective paper, with the correct answer and a full explanation.
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Calculate the variance of 2, 3, 3, 4, 5, 5, 5, 7, 7 and 9
- A. A. 2.2
- B. B. 3.4
- C. C. 4.0
- D. D. 4.2Correct
Explanation
Mean=(2+3+3+4+5+5+5+7+7+9)/10=50/10=5.0. Deviations: -3,-2,-2,-1,0,0,0,2,2,4. Squared: 9,4,4,1,0,0,0,4,4,16, sum=42. Variance=42/10=4.2.
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