310 15 Graph Platforms The Scatterplot 3D Platform
Normal Contour Ellipsoids
A normal contour ellipsoid is a 3-dimensional ellipse that encompasses a specified portion of points.
The ellipsoid is computed from a contour of the multivariate normal distribution fit to the points. The
ellipsoid is a function of the means, standard deviations, and correlations of variables on the plot.
When you add an ellipsoid, two formatting options are available:
• Coverage changes the portion of data points covered by the ellipsoid. The larger the value, the bigger
the ellipsoid.
• Transparency changes the surface of the ellipsoid from transparent to opaque. The larger the value,
the more opaque the ellipsoid.
The coverage and transparency options also appear in ...