Dynamic Graphics for Graphical Models

This demo uses the Graph.Java applet from The Java Boutique.

Risk Factors for Coronary Heart Disease

For a sample of 1841 car-workers, information was recorded on:
  1. whether they smoked (Smoke),
  2. whether their work was mentally strenuous (Mental),
  3. whether their work was physically strenuous (Physical),
  4. whether their systolic blood pressure was lower than 140 (BloodPressure),
  5. whether their liproprotein ratio was less than 3 (Lipo),
  6. and (a potential response) whether they had a family history of coronary heart disease (HeartRisk).

Edwards (1995) describes a stepwise, backward-elimination model selection method which starts from the saturated model and removes successively the least significant edge (pairwise association).

The applet shows the graph for these data at the initial step, before any edges are removed. The edge distances are proportional to the p-value for each edge. (David, p.24). [It's not clear that this is the best metric.] Drag a node around, or click a button, and watch it find a stable configuration reflecting those distances. Press the Scramble button to move the nodes to a new random configuration. Then, try the next stage, after removing the least-significant edges.