Sampling from a multivariate Gaussian distribution

In summary, the conversation discusses a lecture on linear regression and the use of sigma in rotating a distribution. The speaker clarifies that x and y are dummy variables and represent a normal distribution on the x-axis. However, the example given only shows two univariate distributions rather than a multivariate distribution.
  • #1
asilvester635
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0
I was watching a lecture on youtube about linear regression and there's a section where it had the statement below (written in purple). Does multiplying by sigma rotate the distribution to make it look like x - N(mew, sigma^2)? Mew in this case is 0 so it doesn't shift the distribution.

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  • #2
To me ##x## and ##y## are just dummy variables, and both are on the x-axis, or should be, because the y-axis represents the distribution of the probability density, which in this case is a normal distribution. ##y## has its peak at zero on the x-axis, and ##x## has its peak at ##\mu## on the x-axis.
 
  • #3
asilvester635 said:
Sampling from a multivariate Gaussian distribution

The example you gave doesn't illustrate a "multivariate" distribution. It illustrates two univariate distributions.
 

1. What is a multivariate Gaussian distribution?

A multivariate Gaussian distribution is a probability distribution that describes the likelihood of a set of variables, where each variable may have a different mean and variance, being jointly observed. It is often used to model data that is normally distributed and has multiple dimensions.

2. How is sampling from a multivariate Gaussian distribution different from sampling from a univariate Gaussian distribution?

Sampling from a multivariate Gaussian distribution involves generating a random vector of values, while sampling from a univariate Gaussian distribution involves generating a single random value. Additionally, the parameters of a multivariate Gaussian distribution (mean vector and covariance matrix) are more complex than the parameters of a univariate Gaussian distribution (mean and standard deviation).

3. What is the purpose of sampling from a multivariate Gaussian distribution?

Sampling from a multivariate Gaussian distribution is often used in statistical modeling and machine learning to generate random data that follows a specific pattern. This can be useful for testing algorithms or simulating data for research purposes.

4. How is sampling from a multivariate Gaussian distribution implemented in practice?

In practice, sampling from a multivariate Gaussian distribution involves using a computer program or algorithm that can generate random values based on the given mean vector and covariance matrix. This can be done using mathematical formulas or numerical methods such as the Box-Muller transform or the Cholesky decomposition.

5. What are some common applications of sampling from a multivariate Gaussian distribution?

Sampling from a multivariate Gaussian distribution is commonly used in fields such as finance, engineering, and data science for tasks such as portfolio optimization, signal processing, and modeling complex datasets. It is also used in simulation studies and Monte Carlo methods for statistical inference.

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