WAEC Mathematics 2020 Objective — Question 35
Question 35 of 50 from the West African Examinations Council (WAEC) Mathematics 2020 Objective paper, with the correct answer and a full explanation.
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The mean of the numbers 15, 17, 18, 21, 26, 29 is 21. Calculate the standard deviation.
- A. 9
- B. 6
- C. 5Correct
- D. 0
Explanation
Deviations from mean(21): -6,-4,-3,0,5,8; squares: 36,16,9,0,25,64; sum=150. Standard deviation = sqrt(150/6) = sqrt25 = 5.
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