Summary

Linear and Non-Linear Relationships

• A relation is considered a linear relation if the graph produces a straight line.
• Non-linear relations do not form a straight line on a graph.

Types of Variables

• The independent variable does not depend on the other variable.
• The dependent variable depends on the independent variable.

To Connect or Not Connect; That Is the Question.

• If the data or set of points can take on any value between two specified points, the data is continuous and the points are connected on a graph.
• If the data cannot be any of the values between two specified points, the data is discrete and the points are not connected on a graph.

Sketching Graphs

• Be sure to include:
• an appropriate scale
• the labelled axes (including units)
• the dependent variable on the y-axis and the independent variable on the x -axis
• a title
• a line connecting points when applicable (continuous: yes; discrete: no)
• When plotting coordinates, the x-values appear first, followed by the y-values.
• The “squiggle” symbol () on a graph is called an axis break. Axis breaks can be used to exclude unnecessary parts of a graph.