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# Test yourself now

High marks in science are the key to your success and future plans. Test yourself and learn more on Siyavula Practice.

## 23.7 Chapter summary

• An independent variable is not affected by changes in the other variable in a relationship.
• A dependent variable is influenced by the other variable, and changes depending on the relationship with the other variable.
• A linear graph (also called a straight-line graph) shows that the relationship between the independent variable and dependent variable is a straight line.
• For an increasing graph, the dependent variable increases as the independent variable increases.
• For a decreasing graph, the dependent variable decreases as the independent variable increases.
• For a constant linear graph, the dependent variable does not change as the independent variable increases.
• The maximum point on a graph is the point where the dependent variable has the greatest value.
• The minimum point on a graph is the point where the dependent variable has the smallest value.
• Discrete data is made up of quantities that have been counted.
• The plotted points on a discrete graph are not joined by a line.
• Continuous data is made up of quantities that have been measured.
• The plotted points on a continuous graph are joined by a line or curve.
• The Cartesian coordinate system consists of two axes.
• The $$x$$-axis is a horizontal line at $$y = 0$$.
• The $$y$$-axis is a vertical line at $$x = 0$$.
• The point where the two lines intersect is called the origin, (0; 0).
• The $$x$$-axis and the $$y$$-axis divide the Cartesian plane into four quadrants.
• In the first quadrant (I), the values of the $$x$$-axis are positive and the values of the $$y$$-axis are also positive.
• In the second quadrant (II), the values of the $$x$$-axis are negative and the values of the $$y$$-axis are positive.
• In the third quadrant (III), the values of the $$x$$-axis are negative and the values of the $$y$$-axis are also negative.
• In the fourth quadrant (IV), the values of the $$x$$-axis are positive and the values of the $$y$$-axis are negative.
• An ordered pair consists of an $$x$$-value called the $$x$$-coordinate and a $$y$$-value called the $$x$$-coordinate. Notation: $$(x; y)$$