A line graph is used to show how a set of data changes over a period of time. To make a line graph, a scale and interval should be chosen. Then the pairs of data should be graphed and a line connecting the points should be drawn. Consider a table of values that represents the growth of a plant over several weeks.

	Plant Growth
Week	$1$	$2$	$3$	$4$	$5$
Height, $(\text{in})$	$1.5$	$2.3$	$4$	$6.2$	$8$

The height data includes values from $1.5$ to $8,$ so a scale from $0$ to $10$ inches with an interval of $1$ inch are reasonable. The horizontal axis can represent time in weeks and the vertical axis can represent the plant height in inches. Now, the points can be plotted on a coordinate plane and connected.

By observing the upward and downward slant of lines connecting the points, the trends in the data can be described and future events can be predicted.