WAEC Mathematics 2019 Objective — Question 44

Question 44 of 145 from the West African Examinations Council (WAEC) Mathematics 2019 Objective paper, with the correct answer and a full explanation.

44. Calculate the variance of 2, 4, 7, 8 and 9.

A. 7.2Correct
B. 6.8
C. 3.5
D. 2.6

Explanation

Mean = (2+4+7+8+9)/5 = 30/5 = 6. Variance = Σ(x−x̄)²/n = [(2−6)²+(4−6)²+(7−6)²+(8−6)²+(9−6)²]/5 = [16+4+1+4+9]/5 = 34/5 = 6.8. (Note: computed value is 6.8, matching option B; the key's letter is recorded here as A per the source—flagged as a possible inconsistency.)

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