Supplementary materials for:
Elliptical Insights: Understanding Statistical Methods through Elliptical Geometry
Michael Friendly, Georges Monette and John Fox

Documents and files provided here

Visual directory of source code for figures

SAS and R source files are contained in the directories SAS/ and R/ respectively of the Zip file. See the PDF file of Appendices for notes on SAS macros and R packages required to make these run.

The table below shows thumbnails of the figures together with the name of the corresponding SAS or R source file.


Several 3D figures in the printed paper are rendered as static images from different views. These are included here as animated GIF files showing various rotations of these 3D scenes. Click on the image below to see the movies.

Ellipsoids in added-variable plots

3D views of the relationship between Heart, Coffee and Stress, showing the three regression planes for the marginal models of Heart ~ Coffee (green), Heart ~ Stress (pink), and the joint model, Heart ~ Coffee + Stress (light blue). The 2D walls in the figure show the projections of the ellipsoids into the planes of pairs of variables.

Standard view, showing regression planes AV plot view, showing regression planes on edge

Generalized ellipsoids

3D views of an example of generalized ellipsoids. The matrix C1 (blue) generates a proper ellipsoid whose dual (C1^{-1}) is also a proper ellipsoid; matrix C2 (red) generates an improper, flat ellipsoid, whose dual is an unbounded cylinder of elliptical cross section. The scale of these images is defined by a unit sphere (gray).

C2 is a projection of C1 onto the plane where z=0. View illustrating orthogonality of each C and its dual, C^{-1}.

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Elliptical Insights (Supplementary materials) by Michael Friendly is licensed under a Creative Commons Attribution-NonCommercial 3.0 License.