What you'll learn
How to display data clearly and choose an appropriate chart.
Common charts
- Bar chart: categorical or discrete data; equal bar widths, gaps between bars.
- Pie chart: shows proportions of a whole; angle = (frequency ÷ total) × 360°.
- Pictogram: symbols represent frequencies (needs a key).
- Stem-and-leaf diagram: keeps raw values while showing shape; include a key.
- Comparative (dual/composite) bar charts and line graphs for time data.
Choosing a chart
- Match the chart to the data type and the message you want to show.
Exam tips
- Always label axes and include a key/title where needed.
- For pie charts, show the angle calculation.
Common mistakes
- Uneven bar widths or missing gaps.
- Forgetting the key on a pictogram or stem-and-leaf diagram.