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Covariance matrix of a cut-off Multivariate Normal Distribution – IV – theoretical prediction for a 3-dimensional MVN-core

In this post series we study ellipsoidal cores of Multivariate Normal Distributions [MVNs]. We defined a “core” as the volume enclosed by a selected contour surface of constant probability density. We constructed cut-off distributions by setting the probability density to zero outside the core. In previous posts we have already discussed volume integrals which would give us a relation between… Read More »Covariance matrix of a cut-off Multivariate Normal Distribution – IV – theoretical prediction for a 3-dimensional MVN-core

Concentric surfaces of ellipsoids

n-dimensional spheres and ellipsoids – II – volume of n-ellipsoids

This post series provides some insights into the nature of n-dimensional spheres and ellipsoids and the derivation of some special integrals over their volumes. In this 2nd post we look at the volume of a “(n-1)–ellipsoid“. This term refers to a closed ellipsoidal surface in a n-dimensional Euclidean space. Such a surface is a (n-1)-dimensional manifold. See the 1st post… Read More »n-dimensional spheres and ellipsoids – II – volume of n-ellipsoids

n-dimensional spheres and ellipsoids – I – Gamma-function, volume and surface of n-spheres

This post series summarizes some properties of spheres and ellipsoids in a n-dimensional Euclidean space. In addition we are going to study some special integrals over the volume of so called n-spheres and their surfaces. As a preparatory step we look at some useful properties of the so called Gamma-function, which almost automatically appears when one works with integrals in… Read More »n-dimensional spheres and ellipsoids – I – Gamma-function, volume and surface of n-spheres

Cut-off BVN limited to an ellipsoidal core

Covariance matrix of a cut-off Multivariate Normal Distribution – III – results for a 2-dimensional BVN-core and proper normalization of its cut-off distribution

In the math section of this blog, we try to cover interesting aspects of Multivariate Normal Distributions [MVNs]. The topic of this post series is the covariance matrix of a MVN-like distribution confined inside a hyper-surface of constant probability density. Outside of the surface we set the probability density to zero. This gives us a “cut-off” MVN- distribution. Contour surfaces… Read More »Covariance matrix of a cut-off Multivariate Normal Distribution – III – results for a 2-dimensional BVN-core and proper normalization of its cut-off distribution