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. See the Multivariate Methods book for details about multivariate normal distributions.
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Coverage changes the portion of data points covered by the ellipsoid. The larger the value, the bigger the ellipsoid.
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Transparency changes the surface of the ellipsoid from transparent to opaque. The larger the value, the more opaque the ellipsoid.
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You display and remove normal contour ellipsoids by selecting and deselecting Normal Contour Ellipsoids from the red triangle menu.
The examples in this section use the Iris.jmp sample data table, which includes measurements of sepal length, sepal width, petal length, and petal width for three species of iris.