WAEC 2018 · Paper 2 · Q5

Statistics: data & averages

Score	1	2	3	4	5	6
Frequency	2	5	13	11	9	10

The table shows the distribution of scores obtained when a fair die was rolled 50 times.

(a)
Draw a bar chart for the distribution.
Model answer
Put the scores on the horizontal axis and the frequency on the vertical axis, with equal-width bars and equal gaps between them. The bar heights are $2, 5, 13, 11, 9, 10$ ; the tallest bar is at score 3.
(b)
Calculate the mean score of the distribution.

Worked solution (try it first)

(a)

The scores 1 to 6 are separate values, so draw a bar chart: six bars of equal width with equal gaps between them, of heights $2, 5, 13, 11, 9, 10$ .
Label the axes "Score" and "Frequency", and state the scale.

(b)

$\sum fx = 1(2) + 2(5) + 3(13) + 4(11) + 5(9) + 6(10)$
$= 2 + 10 + 39 + 44 + 45 + 60$
$= 200$ and $\sum f = 50$ , so the mean score is $\frac{200}{50} = 4$ .

Report a problem with this question