Data and Line Graphs
Line graphs display data that changes over time, allowing us to see trends, compare values, and make predictions.
What You Need to Know
Key Concept Diagram
A line graph uses points connected by lines to show how a value changes over a continuous period
The horizontal axis (x-axis) usually shows time; the vertical axis (y-axis) shows the measured value
The slope of the line indicates the rate of change: steeper means faster change
Double line graphs compare two sets of data on the same axes using different colours or dashes
Key Vocabulary
Line graph
A graph that uses points connected by lines to show change over time
Trend
A general direction of change shown by the data (going up, going down, or staying flat)
Scale
The numbers marked on an axis that show the range and intervals of the data
Data point
A single piece of information plotted on a graph
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
A line graph shows temperature each hour from 6 am to 12 pm. The line goes steadily upward. What does this tell us?
Question 2
On a line graph, the y-axis goes from 0 to 50 in steps of 10. A point is plotted at the 3rd step. What value does it represent?
Question 3
Which type of data is best shown on a line graph?
Key Concepts Summary
- ●A line graph uses points connected by lines to show how a value changes over a continuous period
- ●The horizontal axis (x-axis) usually shows time; the vertical axis (y-axis) shows the measured value
- ●The slope of the line indicates the rate of change: steeper means faster change
- ●Double line graphs compare two sets of data on the same axes using different colours or dashes