Data Visualization Workshop

Professor Forrest Young, Psychometric Laboratory at the University of North Carolina, Chapel Hill, will present a one-day workshop on Friday, February 3, 1995 in the Administrative Studies Building, Room 031 at York University, Toronto, ONT, describing...


The Visual Statistics System

The workshop will consist of two sessions: 9am-12 noon and 1pm-4pm. (If your WWW browser supports images and imagemaps, click here for a York Campus map).

9am-12: Visual Methods for Statistical Data Analysis

ViSta, a new statistical data visualization system, will be discussed and demonstrated in a non-technical, intuitive and entirely visual presentation. The goal of the system is to provide the statistical data analyst with visual methods that improve the quality, accuracy and satisfaction of the data analysis process. The system works under Microsoft Windows, on Macintosh computers, and under XWindows.

The system includes visualization methods which fall into five major areas:

  1. Visual Guidance (GuideMaps): To guide novice data analysts, the steps which expert data analysts think should be taken to complete a particular data analysis are presented as a map. The map is dynamic, and through computer/analyst interactions, guides the analyst through the analysis.
  2. Session Visualization (WorkMaps): To aid analysts at all levels of expertise, a map is constructed of the steps taken during the data analysis session. This map acts as a memory aid, and can be used to review earlier steps or commence new analyses.
  3. Structure Visualization (SpreadPlots): To aid hypothesis formation and confirmation, pictures are presented showing the structure of data and the structure and fit of data analysis results.
  4. Model Re-Vision (Interactive Graphical Modeling): To further aid hypothesis formation and confirmation, model SpreadPlots include graphical tools for revising parameter estimates. The consequences, in terms of the model's structure and fit, are immediately shown to the analyst, who can then make further re-visions if desired.
  5. Visual Guidance Tools (GuideTools): To guide novice data analysts, the expert data analyst has visual tools for creating guidemaps. To create the maps, the expert uses the system to perform prototypical data analyses, indicating the decision steps as well as the analysis steps.

Workmap Guidemap

1pm-4pm: The Implementation of ViSta in LispStat

ViSta, discussed in the morning session, is implemented using the LispStat object-oriented environment for statistical computing and dynamic graphics. A brief introduction to LispStat is presented, with emphasis on its object-oriented and dynamic graphics features. Then, ViSta's object-oriented system architecture is presented, covering its data, model, map, icon, menu and tool objects and the underlying ViSta/Lisp-Stat data analysis language.

This presentation culminates in showing how a programmer develops new model objects within ViSta's open programming environment. The relation of ViSta's architecture to hypertext, hypercode, dataflow languages, visual programming and program visualization will also be discussed. Finally, a cognitive theory about data analysis will be briefly mentioned.

About Forrest Young

Forrest W. Young, Professor of Psychometrics and Biostatistics at the University of North Carolina at Chapel Hill, received his PhD in Psychometrics from the University of Southern California in 1967. His early research interests focused on Multidimensional and Optimal Scaling (for which he was elected the President of the Psychometric Society and received the American Market Research Association's O'Dell award, both in 1981). His research interests then shifted to Statistical Visualization, including the development of Guided Tours and SpreadPlots.

In recent years Prof. Young has worked on visualization techniques for guiding novice data analysts through complex data analyses. This work is based on cognitive-science and artificial-intelligence notions concerning the structuring of the environment in which data analysis occurs. Prof. Young's long-range goal is to develop a public-domain, academically-oriented, extensible visual statistics package that will be useful for teaching introductory statistics, for data analysis by statistically naive researchers, and for advanced research and development in visual statistics.

Obtaining Vista

ViSta is available from Forrest Young's WWW site, at

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