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The assumption of normality in data has been considered in the field of statistical analysis for a long time. However, in many practical situations, this assumption is clearly unrealistic. It has recently been suggested that the use of…

Computation · Statistics 2016-11-25 Reinaldo B. Arellano-Valle , Javier E. Contreras-Reyes

The skew-normal and the skew-$t$ distributions are parametric families which are currently under intense investigation since they provide a more flexible formulation compared to the classical normal and $t$ distributions by introducing a…

Methodology · Statistics 2012-03-13 Adelchi Azzalini , Reinaldo B. Arellano-Valle

Mixtures of skew-t distributions offer a flexible choice for model-based clustering. A mixture model of this sort can be implemented using a variety of formulations of the skew-t distribution. Herein we develop a mixture of skew-t factor…

Methodology · Statistics 2017-10-09 Paula M. Murray , Ryan P. Browne , Paul D. McNicholas

For the extended skew-normal distribution, which represents an extension of the normal (or Gaussian) distribution, we focus on the properties of the log-likelihood function and derived quantities in the the bivariate case. Specifically, we…

Statistics Theory · Mathematics 2023-09-20 Stefano Franco , Adelchi Azzalini

In many situations we are interested in modeling real data where the response distribution, even conditionally on the covariates, presents asymmetry and/or heavy/light tails. In these situations, it is more suitable to consider models based…

Methodology · Statistics 2024-06-06 João Victor B. de Freitas , Caio L. N. Azevedo

Finite mixtures of matrix normal distributions are a powerful tool for classifying three-way data in unsupervised problems. The distribution of each component is assumed to be a matrix variate normal density. The mixture model can be…

Methodology · Statistics 2013-03-07 Cinzia Viroli

The unified skew-t (SUT) is a flexible parametric multivariate distribution that accounts for skewness and heavy tails in the data. A few of its properties can be found scattered in the literature or in a parameterization that does not…

Methodology · Statistics 2023-12-01 Kesen Wang , Maicon J. Karling , Reinaldo B. Arellano-Valle , Marc G. Genton

Matrix-variate distributions are a recent addition to the model-based clustering field, thereby making it possible to analyze data in matrix form with complex structure such as images and time series. Due to its recent appearance, there is…

Machine Learning · Statistics 2025-08-04 Katharine M. Clark , Paul D. McNicholas

Filtering and smoothing algorithms for linear discrete-time state-space models with skew-t distributed measurement noise are presented. The proposed algorithms improve upon our earlier proposed filter and smoother using the mean field…

Systems and Control · Computer Science 2016-03-22 Henri Nurminen , Tohid Ardeshiri , Robert Piche , Fredrik Gustafsson

Large, non-Gaussian spatial datasets pose a considerable modeling challenge as the dependence structure implied by the model needs to be captured at different scales, while retaining feasible inference. Skew-normal and skew-t distributions…

Methodology · Statistics 2017-12-07 Felipe Tagle , Stefano Castruccio , Marc G. Genton

Parametric distributions are an important part of statistics. There is now a voluminous literature on different fascinating formulations of flexible distributions. We present a selective and brief overview of a small subset of these…

Statistics Theory · Mathematics 2020-05-15 Sharon X. Lee , Geoffrey J. McLachlan

In this paper, we propose finite mixtures of multivariate skew Laplace distributions to model both skewness and heavy-tailedness in the heterogeneous data sets. The maximum likelihood estimators for the parameters of interest are obtained…

Statistics Theory · Mathematics 2017-02-03 Fatma Zehra Doğru , Y. Murat Bulut , Olcay Arslan

Three-way data structures, characterized by three entities, the units, the variables and the occasions, are frequent in biological studies. In RNA sequencing, three-way data structures are obtained when high-throughput transcriptome…

Methodology · Statistics 2022-06-22 Anjali Silva , Steven J. Rothstein , Paul D. McNicholas , Xiaoke Qin , Sanjeena Subedi

In this paper, we propose a novel optimization criterion that leverages features of the skew normal distribution to better model the problem of personalized recommendation. Specifically, the developed criterion borrows the concept and the…

Information Retrieval · Computer Science 2020-05-28 Chuan-Ju Wang , Yu-Neng Chuang , Chih-Ming Chen , Ming-Feng Tsai

We establish an identity for E f (Y) -E f (X), when X and Y both have matrix variateskew-normal distributions and the function f fulfills some weak conditions. Thecharacteristic function of matrix variate skew normal distribution is then…

Statistics Theory · Mathematics 2021-03-10 Tong Pu , Narayanaswamy Balakrishnan , Chuancun Yin

We introduce an extension of finite mixture models by incorporating skew-normal distributions within a Hidden Markov Model framework. By assuming a constant transition probability matrix and allowing emission distributions to vary according…

Methodology · Statistics 2025-09-25 Andrea Nigri , Marco Forti , Han Lin Shang

The multivariate extended skew-normal distribution allows for accommodating raw data which are skewed and heavy tailed, and has at least three appealing statistical properties, namely closure under conditioning, affine transformations, and…

Methodology · Statistics 2015-06-19 Mathieu Gerber , Florian Pelgrin

Skewness is often present in a wide range of spatial prediction problems, and modeling it in the spatial context remains a challenging problem. In this study a skew-Gaussian random field is considered. The skew-Gaussian random field is…

Methodology · Statistics 2014-02-06 Kjartan Rimstad , Henning Omre

Multivariate scale mixtures of skew-normal (SMSN) variables are flexible models that account for non-normality in multivariate data scenarios by tail weight assessment and a shape vector representing the asymmetry of the model in a…

Methodology · Statistics 2018-06-22 Jorge M. Arevalillo , Hilario Navarro

We introduce a novel matrix-variate extension of the Heckman selection model to accommodate multiple outcomes, providing a flexible and natural generalization of classical selection models for matrix-valued data. By relying on the matrix…

Methodology · Statistics 2026-05-05 Heeju Lim , Carlos A. R. Diniz , Ofer Harel , Victor H. Lachos