Graphing Basics

A proper graph is necessary in order to allow you and others to both interpret and analyze your data.  A graph should have all the following elements.

1. Title
   All graphs should have a descriptive title which describes what data the graph is showing.
2. Labeled Axes
   Each axis must be clearly labeled showing the variable being measured along with correct units.
3. Origin
   Always include the origin (0,0) in your graph.  This will help you to properly interpret your data.
4. Data Points with Point Protectors
   Data points should be plotted in the proper position.  Place point protectors (usually circles) around each data point.
5. Proper Scaling
   The graph must be properly scaled.  Scale each axis to take up a maximum amount of space on the page yet maintaining divisions which make plotting as easy as possible.
6. Line or Curve of Best Fit
   Draw a line or curve of best fit.  This line or curve should show the overall tendency of the data. If drawing a line use a straight edge.  Never connect successive data points like you are doing a connect the dots drawing.
7. Identify Points used to Calculate a Slope
   When calculating the slope of a line of best fit choose two points that lie on the line of best fit.  Do not choose data points.  Mark the points you have chosen with a +.
8. One Graph per Page
   The graph should fill the page.  Large graphs are easier to read and easier to interpret.  Draw only one graph per page.  The graph should be as large as the paper and scaling techniques will allow.  Do not try to fit a data table onto the page as well.

Example Graph shown below