Graphs and Charts

The sample memo report shows examples of graphical presentations of data. Remember that you are trying to communicate information to the reader. Some guidelines for effective presentation of graphical information are the following:

1. Be neat. Draw graphs using straight edge and french curve. Don't draw graphs free hand.

2. Title all graphs and charts. What is the graph supposed to convey?

3. Label all axis, giving units.

4. Plot dependent variables on the y axis (ordinate). The independent variable is usually on the x axis (abscissa). For example, in the equation y = mx + b, y is the dependent and x the independent variables.

5. Plot data to be compared on one graph to allow the reader to easily see differences and similarities. However, don't put too much information on one graph. An uncluttered graph is more effective.

6. Use different types of marks (crosses, squares, circles, etc.) for data points on multi curve graphs. Since colors do not reproduce well, use different types of lines (dotted, dashed, solid etc.).

7. Plot the data either as a smooth curve or connect point-to-point depending on the information to be presented. You will learn with experience what works best. When in doubt, ask an instructor.

8. Choose the type of graph paper (linear, semi-log, log-log etc.) depending on the information to be presented.