Question

11. The table shows the distribution of the number of hours per day spent studying by 50 students (hours: 4–11; frequencies: 5,7,5,9,12,4,3,5). Calculate, correct to two decimal places, the: (a) mean; (b) standard deviation.

Model answer

(a) Mean = Σfx/Σf = 365/50 = 7.30. (b) Standard deviation = √(Σf(x-x̄)²/Σf) = √(208.5/50) = √4.17 = 2.04.

Accepted Answer

(a) Mean = Σfx/Σf = 365/50 = 7.30.
(b) Standard deviation = √(Σf(x-x̄)²/Σf) = √(208.5/50) = √4.17 = 2.04.

WAEC Mathematics 2021 Theory — Question 18

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