Plotting p^k Factorial or p^n-k Fractional Factorial Data

Abstract

This department publishes articles of interest to statistical practitioners. Innovative applications of known methodology may be suitable, but sizable case studies should be submitted to other journals. Brief descriptions and illustrations of new developments that are potentially useful in statistical practice are appropriate. Acceptable articles should appeal to a substantial number of practitioners.

This article gives a plotting algorithm for viewing the data from p^k factorial or p^−k fractional factorial experiments. The raw data are displayed in a tree structure where the order of the tree is determined by increasing sums of squares from an analysis of variance model. For small factorial experiments this display allows the experimenter to identify outlying points, see the design structure for fractional factorials, and get a feel for the main effects and interactions present. A computer code written is S that produces the factorial data plot is available from the author.

Key Words:

• Analysis of variance
• Computer code
• Graphics
• Interactions