The idea, step by step
Choose for the job
A table is useful when exact values matter. A column graph makes separate categories easy to compare. A line graph can show how a measurement changes through ordered time. Choose a display because it helps answer the question, not because it looks exciting.
Favourite-fruit answers are separate categories. Use equal-width columns with equal gaps. Do not join their tops with a line as if apples happened before bananas.
A fair graph
Give a graph a title. Label its categories and number axis, including measurement units when needed. Use equal intervals on a number scale. For our simple column graphs, start at zero so column heights fairly represent the counts.
If one interval represents two votes, label 0, 2, 4, 6, 8. Do not change the scale partway up. A picture graph needs a key if one picture represents more than one item.
A common trap
A line graph is suitable for any list of numbers.
Instead: Join points only when their order and connection make sense, such as measurements through time.
See the thinking
Compare choices
Which display makes the favourite-fruit counts easy to compare?
| Fruit | Votes |
|---|---|
| Apples | 8 |
| Bananas | 6 |
| Oranges | 4 |
| Pears | 2 |
- The answers are separate categories.
- A column for each fruit allows direct comparison of heights.
- Label the number axis Votes and start at zero with equal steps.
Look up an exact value
A coach needs each runner's finishing time to the nearest second. Would a table help?
- The coach needs an exact value for each runner.
- A table can pair a runner's code with a time in seconds.
- A graph might show a pattern, but it should not replace the exact records.
Check your understanding
Choose a column graph or line graph to compare numbers of red, blue and green counters.
Show answer
A column graph.
Colours are separate categories, not an ordered time sequence.
Your turn
6 questions · 9 marks · Work at your own pace.
Read the questions online
- Choose a display for the number of pupils choosing each of four sports.1 mark
- Choose a display for temperature recorded each hour through one day.1 mark
- Choose a display to look up the exact price of each lunch item.1 mark
- What does the vertical axis of the supplied fruit graph measure?1 mark
- Equal grid intervals on a graph are labelled 0, 2, 4, 8, 10. Is this scale fair?2 marks
- Draw a column graph for Cat 4, Dog 6, Bird 2. Give it a title, labels and fair scale.3 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- Choose a display for the number of pupils choosing each of four sports.1 mark
The sports are separate categories; compare their counts.
A column graph. - Choose a display for temperature recorded each hour through one day.1 mark
Ordered time shows how a measurement changes.
A line graph. - Choose a display to look up the exact price of each lunch item.1 mark
A table pairs each item with its exact price.
A table. - What does the vertical axis of the supplied fruit graph measure?1 mark
The axis label names the count represented by column height.
Number of votes. - Equal grid intervals on a graph are labelled 0, 2, 4, 8, 10. Is this scale fair?2 marks
The changes are 2, 2, 4 and 2.
A consistent scale could be 0, 2, 4, 6, 8.
No. Equal distances must represent equal changes. - Draw a column graph for Cat 4, Dog 6, Bird 2. Give it a title, labels and fair scale.3 marks
Use equal-width columns and equal gaps.
Label each category and the number axis.
A valid graph has Cat, Dog and Bird columns of heights 4, 6 and 2; title Favourite pet; vertical axis Votes from 0 to 6 in equal steps.
Curriculum reference & lesson scope
Australian Curriculum v9 / SA Curriculum 2026
Data types/validation; mode; suitable displays; line graphs; statistical investigations.
Official curriculum source ↗