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Hauptverfasser: Jiang, Fen, Zhao, Jianhua, Shang, Changchun, Ma, Xuan, Wang, Yue, Tao, Ye
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2505.00361
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author Jiang, Fen
Zhao, Jianhua
Shang, Changchun
Ma, Xuan
Wang, Yue
Tao, Ye
author_facet Jiang, Fen
Zhao, Jianhua
Shang, Changchun
Ma, Xuan
Wang, Yue
Tao, Ye
contents Matrix-valued data, where each observation is represented as a matrix, frequently arises in various scientific disciplines. Modeling such data often relies on matrix-variate normal distributions, making matrix-variate normality testing crucial for valid statistical inference. Recently, the Distance-Distance (DD) plot has been introduced as a graphical tool for visually assessing matrix-variate normality. However, the Mahalanobis squared distances (MSD) used in the DD plot require vectorizing matrix observations, restricting its applicability to cases where the dimension of the vectorized data does not exceed the sample size. To address this limitation, we propose a novel graphical method called the Matrix Healy (MHealy) plot, an extension of the Healy plot for vector-valued data. This new plot is based on more accurate matrix-based MSD that leverages the inherent structure of matrix data. Consequently, it offers a more reliable visual assessment. Importantly, the MHealy plot eliminates the sample size restriction of the DD plot and hence more applicable to matrix-valued data. Empirical results demonstrate its effectiveness and practicality compared to the DD plot across various scenarios, particularly in cases where the DD plot is not available due to limited sample sizes.
format Preprint
id arxiv_https___arxiv_org_abs_2505_00361
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Matrix Healy Plot: A Practical Tool for Visual Assessment of Matrix-Variate Normality
Jiang, Fen
Zhao, Jianhua
Shang, Changchun
Ma, Xuan
Wang, Yue
Tao, Ye
Methodology
Matrix-valued data, where each observation is represented as a matrix, frequently arises in various scientific disciplines. Modeling such data often relies on matrix-variate normal distributions, making matrix-variate normality testing crucial for valid statistical inference. Recently, the Distance-Distance (DD) plot has been introduced as a graphical tool for visually assessing matrix-variate normality. However, the Mahalanobis squared distances (MSD) used in the DD plot require vectorizing matrix observations, restricting its applicability to cases where the dimension of the vectorized data does not exceed the sample size. To address this limitation, we propose a novel graphical method called the Matrix Healy (MHealy) plot, an extension of the Healy plot for vector-valued data. This new plot is based on more accurate matrix-based MSD that leverages the inherent structure of matrix data. Consequently, it offers a more reliable visual assessment. Importantly, the MHealy plot eliminates the sample size restriction of the DD plot and hence more applicable to matrix-valued data. Empirical results demonstrate its effectiveness and practicality compared to the DD plot across various scenarios, particularly in cases where the DD plot is not available due to limited sample sizes.
title Matrix Healy Plot: A Practical Tool for Visual Assessment of Matrix-Variate Normality
topic Methodology
url https://arxiv.org/abs/2505.00361