Graphical Insight and Data Analysis for the 2,2,2 Crossover Design

  • Bill Pikounis
  • Thomas E. Bradstreet
  • Steven P. Millard


S-Plus code is presented for the graphical insight into, and the statistical analysis of, a two-treatment, two-period, two-treatment-sequence, or 2,2,2 crossover design. In this introductory section, we describe the 2,2,2 crossover design and its uses in the pharmaceutical industry with emphasis on food interaction studies. We also introduce a specific example and a dataset which will be used pedagogically throughout the chapter. In Section 7.2, we provide a brief introduction to data management in S-Plus demonstrating just enough manipulations to facilitate the graphical methods and data analyses which follow. Section 7.3 presents a series of graphs for the initial exploration and discovery stage of the analysis of the 2,2,2 crossover design. In Section 7.4, we perform the usual normal theory ANOVA and provide a clear and decision-oriented summary and inference plot. Section 7.5 presents several graphical tools for the “visualization of the ANOVA” and a subsequent model fit assessment, and we end with a summary in Section 7.6.


Model Check Sequence Effect Treatment Sequence Crossover Design Data Frame 
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Copyright information

© Springer Science+Business Media New York 2001

Authors and Affiliations

  • Bill Pikounis
    • 1
  • Thomas E. Bradstreet
    • 2
  • Steven P. Millard
    • 3
  1. 1.Merck Research LaboratoriesRahwayUSA
  2. 2.Merck Research LaboratoriesBlue BellUSA
  3. 3.Probability, Statistics & InformationSeattleUSA

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