Shape Mixture Models Based on Multivariate Extended Skew Normal Distributions

Author(s):  
Weizhong Tian ◽  
Tonghui Wang ◽  
Fengrong Wei ◽  
Fang Dai
2021 ◽  
Author(s):  
Tiago Dias Domingues ◽  
Helena Mouriño ◽  
Nuno Sepúlveda

AbstractFinite mixture models have been widely used in antibody (or serological) data analysis in order to help classifying individuals into either antibody-positive or antibody-negative. The most popular models are the so-called Gaussian mixture models which assume a Normal distribution for each component of a mixture. In this work, we propose the use of finite mixture models based on a flexible class of scale mixtures of Skew-Normal distributions for serological data analysis. These distributions are sufficiently flexible to describe right and left asymmetry often observed in the distributions associated with hypothetical antibody-negative and antibody-positive individuals, respectively. We illustrate the advantage of these alternative mixture models with a data set of 406 individuals in which antibodies against six different human herpesviruses were measured in the context of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.


2009 ◽  
Vol 79 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Natalia Lysenko ◽  
Parthanil Roy ◽  
Rolf Waeber

2018 ◽  
Vol 61 (6) ◽  
pp. 2643-2670
Author(s):  
Wan-Lun Wang ◽  
Ahad Jamalizadeh ◽  
Tsung-I Lin

Author(s):  
Víctor Hugo Lachos Dávila ◽  
Celso Rômulo Barbosa Cabral ◽  
Camila Borelli Zeller

2015 ◽  
Vol 45 (3) ◽  
pp. 794-803
Author(s):  
Shimin Zheng ◽  
Jeff Knisley ◽  
Kesheng Wang

2019 ◽  
Vol 79 (3) ◽  
pp. 577-597
Author(s):  
Sookyoung Son ◽  
Hyunjung Lee ◽  
Yoona Jang ◽  
Junyeong Yang ◽  
Sehee Hong

The purpose of the present study is to compare nonnormal distributions (i.e., t, skew-normal, skew- t with equal skew and skew- t with unequal skew) in growth mixture models (GMMs) based on diverse conditions of a number of time points, sample sizes, and skewness for intercepts. To carry out this research, two simulation studies were conducted with two different models: an unconditional GMM and a GMM with a continuous distal outcome variable. For the simulation, data were generated under the conditions of a different number of time points (4, 8), sample size (300, 800, 1,500), and skewness for intercept (1.2, 2, 4). Results demonstrate that it is not appropriate to fit nonnormal data to normal, t, or skew-normal distributions other than the skew- t distribution. It was also found that if there is skewness over time, it is necessary to model skewness in the slope as well.


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