Line Graphs - Year 7 PDF Download

Introduction

• A line graph is a visual representation that helps in identifying patterns in data over time, such as tracking changes in hours over a day or months within a year. It connects data points using line segments for clearer visualization.
• When depicting information in a line chart, the vertical scale typically indicates the frequency of occurrences, while the horizontal scale signifies the time intervals. This setup aids in understanding how data changes over time.
• Certain line graphs incorporate a false origin, a feature that allows for adjusting the starting point of the vertical scale to better illustrate data trends accurately.

How to create a line graph

• To begin creating a line graph, you need data typically presented in a table format.
• To create a line graph, follow these steps:
  • Identify the highest frequency in your data table.
  • Draw a vertical axis on your graph paper.
  • Select an appropriate scale for this axis and label it up to the highest frequency.
  • Determine the number of subdivisions needed for the horizontal axis.
  • Draw and label the horizontal axis.
  • Plot each data point according to the frequencies and time intervals.
  • Connect each data point to the next with straight lines.
  • Ensure both axes are correctly labeled, and add a title to your line graph.

Example

Example: The line graph below shows the number of parcel deliveries completed on each day of the week.
How many parcels were delivered on Wednesday?
Sol: The number of parcels delivered on Wednesday is 102
A false origin has been used on the vertical scale.
The scale is going up in increments of 20
Between each multiple of 20 is ten subdivisions.
Each subdivision is worth two parcels.

Real-life maths

• An investor is a person who puts money (capital) into something with the expectation of a future financial return. They might use line graphs to track the value of companies over time. 
• By watching the rise and fall in a company's share value, they might be able to work out a good time to buy and sell shares in order to get the best return.