Multivariate Probability Distribution is a type of probability distribution involving multiple random variables. This is contrasted to Univariate Probability Distributions

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Multi Model Probability Distribution is a model comprised of an unspecified combination of multiple probability distribution functions (univariate and/or multivariate)

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Multivariate vs Mixture

Multivariate	Mixture
a Multivariate Model is defined as a 𝑘 dimensional random vector	a Mixture Model is defined as a random variable (which you can call a 1-dimensional random vector)
a Multivariate Model will strictly have a joint distribution of multiple variables	a Mixture Model can have either a distribution of one variable or joint distribution of more than one variable as the underlying distribution

Multivariate & Mixture Model Examples