Linear images of a normal vector

Proposition taught in Covariance and the multivariate normal, part of Statistical learning

Linear images of a normal vector

Type Proposition
Taught in Covariance and the multivariate normal
Part Statistical learning

Let \mathbf{X}\sim\operatorname{N}_p(\boldsymbol{\mu},\Sigma) with \Sigma of rank p, and let A be an m\times p matrix of rank m\le p. Then \mathbf{Y}=A\mathbf{X} satisfies

\mathbf{Y}\sim\operatorname{N}_m(A\boldsymbol{\mu},\,A\Sigma A^\top).

Used in

See also

Affine images of normal vectors · Joint distribution and density · Mean vector and covariance matrix · Correlation · Multivariate normal distribution · Squared Mahalanobis distance · Conditional distribution of a multivariate normal · Partial correlation

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