Handling Data 2
3 marks · NormalThe table shows the time, t (minutes), several students spent revising for a test.
| Time (t, min) | Frequency |
|---|---|
| 0 ≤ t < 10 | 2 |
| 10 ≤ t < 20 | 5 |
| 20 ≤ t < 30 | 8 |
| 30 ≤ t < 40 | 3 |
Draw a frequency polygon using this data. Plot the mid-points of each group on the horizontal axis and frequency on the vertical axis.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Must show: points at (5,2), (15,5), (25,8), (35,3) joined by straight lines
Common mistakes: Using class boundaries instead of mid-points
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Calculates mid-points of all groups correctly (5,15,25,35)
M1 · 1 mark · Plots frequency polygon points (mid-point, frequency)
A1 · 1 mark · Joins points in order with straight lines; axes labelled clearly
Worked solution
Find mid-points: 0–10 = 5, 10–20 = 15, 20–30= 25, 30–40=35