GB-32-06-001 · Drawing a histogram
Draw a histogram on squared paper for this grouped data. Label both axes.
| Mass m (g) | Frequency |
|---|---|
| 0 < m ≤ 10 | 12 |
| 10 < m ≤ 20 | 9 |
| 20 < m ≤ 40 | 13 |
Histograms: Drawing
Booklet p. 72
Method
1) Find each class width
2) Divide frequency by class width
3) Draw touching bars using frequency density as the height
Worked Example (GB-32-06-001)
1)
| Class | Frequency f | Class width | Frequency density |
|---|---|---|---|
| 0 < m ≤ 10 | 12 | 10 | |
| 10 < m ≤ 20 | 9 | 10 | |
| 20 < m ≤ 40 | 13 | 20 |
2)
Use mass (g) on the horizontal axis and frequency density on the vertical axis. Draw touching bars over the stated intervals with the calculated heights; their areas represent frequencies.
3)
Ans =
Bar heights 1.2, 0.9, 0.65 on a frequency-density axis.