WJEC Maths for AS: Applied sample

2 Data presentation and interpretation 20 Example 1 Some students in a school class took a geography examination. The unϐinished table and histogram show information about the marks in the examination. Mark (%) Freq ency 0 < x ≤ 20 5 20 < x ≤ 50 50 < x ≤ 60 25 60 < x ≤ 80 10 80 < x ≤ 85 85 < x ≤ 100 30 Complete the table and the histogram. 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 10 20 30 40 50 60 70 80 90 100 Mark (%) Frequency density Answer 1 To ϐind the frequency of the second bar, frequency = area of bar = class width × frequency density = 30 × 0.5 = 15. To ϐind the frequency of the bar with class interval 80 < x ≤ 85, frequency = area of bar = class width × frequency = 5 × 3 = 15 Hence the completed table is Mark (%) Frequency 0 < x ≤ 20 5 20 < x ≤ 50 15 50 < x ≤ 60 25 60 < x ≤ 80 10 80 < x ≤ 85 15 85 < x ≤ 100 30