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Briefly, the variance for a variable is a measure of the dispersion or spread of scores. Covariance indicates how two variables vary together.

The variance-covariance matrix is a compact way to present data for your variables. The variance is presented on the diagonal (where the column and row intersect for the same variable), while the covariances reside above or below the diagonal.

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How do you calculate a variance covariance matrix explain with an example?

variance - covariance - how to calculate and its uses


How 2 calculate a variance covariance matrix?

look in a maths dictionary


How prove that variance-covariance matrix is nonnegative definite?

To prove that the variance-covariance matrix ( \Sigma ) is nonnegative definite, we can show that for any vector ( x ), the quadratic form ( x^T \Sigma x \geq 0 ). The variance-covariance matrix is defined as ( \Sigma = E[(X - E[X])(X - E[X])^T] ), where ( X ) is a random vector. By substituting ( x^T \Sigma x ) and using the properties of expected values and the definition of variance, we find that the expression equals the variance of the linear combination of the components of ( X ), which is always nonnegative. Thus, ( \Sigma ) is nonnegative definite.


What is the meaning of analysis of covariance?

A mix of linear regression and analysis of variance. analysis of covariance is responsible for intergroup variance when analysis of variance is performed.


How do you calculate a variance-covariance matrix explain with an example?

Here's a link to a website that has an example http://www.itl.nist.gov/div898/handbook/pmc/section5/pmc541.htm and another example for understanding covariance and variance http://www.visualstatistics.net/Visual%20Statistics%20Multimedia/covariance.htm


Distinguish between analysis of variance and analysis of covariance?

) Distinguish clearly between analysis of variance and analysis of covariance.


What is difference between covariance and variance?

Covariance: An Overview. Variance refers to the spread of a data set around its mean value, while a covariance refers to the measure of the directional relationship between two random variables.


What is the significance of the sigma matrix in the context of linear algebra and how is it used in mathematical computations?

The sigma matrix, also known as the covariance matrix, is important in linear algebra because it represents the relationships between variables in a dataset. It is used to calculate the variance and covariance of the variables, which helps in understanding the spread and correlation of the data. In mathematical computations, the sigma matrix is used in various operations such as calculating eigenvalues and eigenvectors, performing transformations, and solving systems of linear equations.


How do you get to pca?

To get to PCA (Principal Component Analysis), you first standardize your data to ensure each feature contributes equally. Next, you compute the covariance matrix to understand how variables interact. Then, you perform eigenvalue decomposition on the covariance matrix to identify principal components, which are the new axes that capture the most variance in the data. Finally, you project your original data onto these principal components for dimensionality reduction.


What is significance of diagonal terms of variance-covariance matrix?

The diagonal terms give the variances. The square root of which gives the standard deviations. The diagonal terms give the variances. The square root of which gives the standard deviations.


Where can one find information on the covariance matrix?

One can find information on the covariance matrix on the Wikipedia website where there is much information about the mathematics involved. One can also find information on Mathworks.


What has the author Tony Lancaster written?

Tony Lancaster has written: 'The covariance matrix of the information matrix test'