4.8.2 Scatter Graph

A scatter graph, also known as a scatter plot, is a type of chart used to display the relationship between two variables. 

• In a scatter graph, each data point represents a combination of values for the two variables being plotted.

• The horizontal axis of the scatter graph represents one variable, while the vertical axis represents the other variable. 

• Each point on the graph corresponds to a particular value of both variables. 

• The position of the point on the graph indicates the value of each variable for that data point.

• Scatter graphs are useful for identifying patterns or trends in data and for visualizing the strength and direction of the relationship between two variables. 

• A scatter graph can be used to identify whether the variables have a positive or negative correlation, or whether there is no correlation between them.

To draw a scatter graph, follow these steps:

• Choose the two variables you want to plot on the graph. 

  • One variable should be assigned to the \( x \)-axis (horizontal axis), and the other variable should be assigned to the \( y \)-axis (vertical axis).

• Determine the range of values for each variable and scale the axes accordingly. 

  • The scales should be evenly spaced, and the interval between each tick mark should be the same on each axis.

• Plot each data point on the graph using a symbol or a dot. 

  • The location of each data point on the graph corresponds to the value of the \( x \)-axis and \( y \)-axis variables.

• Once all data points have been plotted, examine the overall pattern of the data. 

  • Determine if there is a relationship between the two variables, and if so, what type of relationship it is (positive, negative, or no correlation).

• If desired, you can add a trend line (a straight line that best fits the data points) to the graph to help illustrate the relationship between the two variables.

• Label the \( x \)-axis and \( y \)-axis with the name of the variables and their units of measurement.

• Add a title to the graph that accurately describes the data being displayed.

• Finally, make sure the graph is easy to read and visually appealing by adjusting the font size, colors, and layout as needed.