Abstract
How to Explain Interaction without Statistics: Graphical Analysis of all Possible Cases on a 2x2 De sign. The objective of the graphic analysis is to improve the comprehension of data obtained from a study with factorial design. All possible situations generated from a 2x2 factorial design are studied. We provide guidelines for a correct interpretation of principal effects when interaction is present. We also re-interpret the concept of 'ordinality' -applied to a figure of the results. Also presented are guidelines for the preparation of figures for journals. The graphic analysis approach is recommended for teaching the concept of interaction to students, and for researchers with little statistical background.
