arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1409.6019stat.MEmath.STstat.COstat.TH
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回归分析中基于污染高斯加权模型的鲁棒聚类

Robust Clustering in Regression Analysis via the Contaminated Gaussian Cluster-Weighted Model

Antonio Punzo, Paul D. McNicholas

摘要:

高斯聚类加权模型(CWM)是具有随机协变量的回归模型的混合,允许对由响应变量和协变量组成的随机向量进行灵活聚类。在每个混合分量中,它对协变量和给定协变量的响应都采用高斯分布。为了鲁棒的方法相对于可能的椭圆重尾偏离正态性,由于存在非典型的观察,污染高斯CWM在这里介绍。除了高斯CWM的参数之外,我们的污染CWM的每个混合成分都有一个控制离群值比例的参数,一个控制杠杆点比例的参数,一个指定相对于响应变量的污染程度,一个指定相对于协变量的污染程度。至关重要的是,这些参数不必事先指定,从而为我们的方法增加了灵活性。此外,一旦模型被估计并且观察被分配到组,则可以直接获得典型点、离群值、好杠杆点和坏杠杆点的更精细的组内分类-稳健回归分析中的首要概念。与其他基于混合的污染模型的关系进行了分析,提供了可识别的条件,期望条件最大化算法概述了参数估计,并讨论了各种实施和操作问题。通过蒙特卡罗实验评价了回归系数估计的性质,并与高斯CWM的估计进行了比较。还根据实际数据集进行了敏感性研究。

英文摘要:

The Gaussian cluster-weighted model (CWM) is a mixture of regression models with random covariates that allows for flexible clustering of a random vector composed of response variables and covariates. In each mixture component, it adopts a Gaussian distribution for both the covariates and the responses given the covariates. To robustify the approach with respect to possible elliptical heavy tailed departures from normality, due to the presence of atypical observations, the contaminated Gaussian CWM is here introduced. In addition to the parameters of the Gaussian CWM, each mixture component of our contaminated CWM has a parameter controlling the proportion of outliers, one controlling the proportion of leverage points, one specifying the degree of contamination with respect to the response variables, and one specifying the degree of contamination with respect to the covariates. Crucially, these parameters do not have to be specified a priori, adding flexibility to our approach. Furthermore, once the model is estimated and the observations are assigned to the groups, a finer intra-group classification in typical points, outliers, good leverage points, and bad leverage points - concepts of primary importance in robust regression analysis - can be directly obtained. Relations with other mixture-based contaminated models are analyzed, identifiability conditions are provided, an expectation-conditional maximization algorithm is outlined for parameter estimation, and various implementation and operational issues are discussed. Properties of the estimators of the regression coefficients are evaluated through Monte Carlo experiments and compared to the estimators from the Gaussian CWM. A sensitivity study is also conducted based on a real data set.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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