Creating a Line Graph (or XY Graph)

Line graphs , or XY graphs, are used to visually display data (the results of an experiment) in such a way as to show the relationship of one factor, such as disease severity, to another factor, such as time.  For a line graph, both factors need to be quantitative in nature, meaning that they can be expressed as a numerical value, such as temperature or time. Qualitative (or catagorical) factors, such as  kinds of trees or eye color, can not be a component of a line graph.  A line graph is set up as a vertical axis (the Y axis) and a horizontal axis (the X axis), forming a grid.  One of the two factors is measured on the Y axis and the other is measured on the X axis.  To create the graph a point is placed on the grid where the value of the X variable and the value of theY variable intersect. A line is then drawn to connect the points on the graph, moving from left to right.