To create interaction plots or graphs with two variables

- It is important to carefully organize the data into columns as shown in the example below. The first column contains information for the x-axis and is the levels (concentrations or codes) used for the first factor in the GLM. The remaining columns contain the measurement data for each cell in the table.

Data for the x-axis Levels of factor 1	Level 1 factor 2	Level 2 factor 2	Level 3 factor 2
Level 1	measurement data	measurement data	measurement data
Level 2	measurement data	measurement data	measurement data
Level 3	measurement data	measurement data	measurement data

• Proceed through the chart wizard as for other graphs.
• For interaction plots select a scatter plot with the lines connected.
• Error bars will be added separately for each line. Use care when adding error bars. Make sure the data you enter goes with the line you used to activate the Format Data Series option.
• The caption should have a complete reporting of the GLM. This means p values should be given for both factors and the interaction.