Finite-sample inference with monotone incomplete multivariate normal data, III: Hotelling’s T2-statistic

2013 ◽  
Vol 13 (5-6) ◽  
pp. 431-457 ◽  
Author(s):  
Megan M Romer ◽  
Donald St. P Richards
2016 ◽  
Vol 78 (4-4) ◽  
Author(s):  
Suryaefiza Karjanto ◽  
Norazan Mohamed Ramli ◽  
Nor Azura Md Ghani

The DNA microarray technologies permit scientists to depict the expression of genes for related samples.  This relationship between genes is analysed using Hotelling’s T2 as a multivariate test statistic but the disadvantage of this test, when used in microarray studies is the number of samples is larger than the number of variables.  This study discovers the potential of the shrinkage approach to estimate the covariance matrix specifically when the high dimensionality problem happened.  Consequently, the sample covariance matrix in Hotelling’s T2 statistic is not positive definite and become singular thus cannot be inverted.  In this research, the Hotelling’s T2 statistic is combined with a shrinkage approach as an alternative estimation to estimate the covariance matrix to detect significant gene sets.  The multivariate test statistic of classical Hotelling's T2 is used to integrate the correlation when assessing changes in activity level across biological conditions.  The performances of the proposed methods were assessed using real data study.  Shrinkage covariance matrix approach indicates a better result for detection of differentially expressed gene sets as compared to other methods.


2021 ◽  
Vol 1988 (1) ◽  
pp. 012116
Author(s):  
Mohd Aizat Ahlam Mohamad Mokhtar ◽  
Nur Syahidah Yusoff ◽  
Chuan Zun Liang

Author(s):  
Martin Klein ◽  
Bimal Sinha

In this paper we develop likelihood-based finite sample inference based on singly imputed partially synthetic data, when the original data follow either a multivariate normal or a multiple linear regression model. We assume that the synthetic data are generated by using the plug-in sampling method, where unknown parameters in the data model are set equal to observed values of their point estimators based on the original data, and synthetic data are drawn from this estimated version of the model. Empirical studies are presented to show that the proposed methods do indeed perform as the theory predicts, and to compare the proposed methods for singly imputed synthetic data with the combining rules that are used to analyze multiply imputed partially synthetic data. Some theoretical comparisons between singly and multiply imputed partially synthetic data inference are also provided. A data analysis example and disclosure risk evaluation of singly and multiply imputed partially synthetic data is presented based on public use data from the Current Population Survey. We discuss the specific conditions under which the proposed methodology will yield valid inference, and evaluate the performance of the methodology when certain conditions do not hold. We outline some ways to extend the proposed methodology for certain scenarios where the required set of conditions do not hold.


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