Data
Line graphs & frequency diagrams
A line graph shows how something changes over time. A frequency diagram is like a bar chart for measured data, with no gaps between the bars.
Two graphs
ā¢ Line graph ā points joined by lines; great for showing change over time (describe it going up, down or staying flat). ā¢ Frequency diagram ā bars with no gaps, used for measured (continuous) data like heights or times.
Worked examples
Reading a line graph
- A temperature graph shows 5 p.m. at the last point.
- Read across to the value.
Answer: The temperature at 5 p.m. is 11Ā°C.
Describing the shape
- The line starts at 3Ā°, rises to 5Ā°, then falls to 2Ā°.
- Describe the overall shape in words.
Answer: The line goes up, then down.
Where you see this in real life
- Showing how temperature changes through the day.
- Tracking the height of a candle as it burns down.
- Recording the heights of dogs in a frequency diagram.
Key words
- Line graph
- A graph that uses lines to join points, showing change over time.
- Frequency diagram
- A bar-style graph for measured data, with no gaps between the bars.
- Axis
- A labelled line on a graph: the x-axis (across) and y-axis (up).