EDEXCEL GCSE FOUNDATION MATHS - What are Line Graphs

Edexcel GCSE Foundation Maths: What are Line Graphs?

Introduction

Line graphs are a powerful tool used to represent data that changes over time. They're often used to track trends, compare values, and highlight patterns in data. In this tutorial, we'll explore the basics of line graphs and how to interpret them.

Key Components

• Horizontal Axis (x-axis): This axis represents the independent variable, typically time. It's labelled with units like years, months, days, or hours.
• Vertical Axis (y-axis): This axis represents the dependent variable, the value that changes with respect to time. It's labelled with units relevant to the data being plotted.
• Data Points: Each point on the graph represents a specific data value at a particular time.
• Line: The line connects the data points, showing the trend or relationship between the data values over time.

Interpreting Line Graphs

1. Identify the axes: Determine what the x-axis and y-axis represent. This will tell you what the graph is showing.
2. Read the scale: Understand the units and increments on each axis to accurately interpret the data.
3. Locate data points: Find specific data values by looking at the point where the line intersects with the axes.
4. Analyze the trend: Observe the direction of the line.
   • Upward Trend: Indicates an increase in the dependent variable over time.
   • Downward Trend: Indicates a decrease in the dependent variable over time.
   • Horizontal Trend: Indicates no change in the dependent variable over time.
5. Look for patterns: Examine the line graph for any noticeable patterns or fluctuations. Are there sudden jumps or dips in the data? Are there any periods of steady growth or decline?

Example:

        Temperature (°C)
        |        
    15    *
        |    *
    10    *  * 
        |  *  *
     5    *  *  * 
        | *  *  * 
     0  *  *  *  * 
        ------------------------
             Time (hours)
             0 2 4 6 8 10 12

This line graph shows the temperature over a 12-hour period. We can see:

• The temperature starts at 0°C.
• It increases steadily until around hour 6.
• Then, the temperature remains relatively constant for a few hours.
• Finally, the temperature drops slightly towards the end of the period.

Creating Line Graphs

1. Choose appropriate axes: Decide what variables will be represented on each axis.
2. Label and scale the axes: Clearly label the axes and choose an appropriate scale for the data.
3. Plot the data points: Mark each data point with a dot or a small symbol.
4. Connect the points: Draw a line connecting the data points in order.

Applications

Line graphs are widely used in:

• Finance: Tracking stock prices, interest rates, and economic indicators
• Science: Monitoring growth patterns, experiments, and weather conditions
• Health: Analyzing patient vitals, disease trends, and medication effectiveness
• Business: Analyzing sales figures, marketing campaigns, and company performance

By understanding the basics of line graphs, you'll be able to interpret and analyze data effectively, making informed decisions and drawing meaningful conclusions.