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Full-Text Articles in Physical Sciences and Mathematics
Estimating And Testing Treatment Effects With Misclassified Multivariate Data, Zi Ye
Estimating And Testing Treatment Effects With Misclassified Multivariate Data, Zi Ye
Theses and Dissertations--Statistics
Clinical trials are often used to assess drug efficacy and safety. Participants are sometimes pre-stratified into different groups by diagnostic tools. However, these diagnostic tools are fallible. The traditional method ignores this problem and assumes the diagnostic devices are perfect. This assumption will lead to inefficient and biased estimators. In this era of personalized medicine and measurement-based care, the issues of bias and efficiency are of paramount importance. Despite the prominence, only few researches evaluated the treatment effect in the presence of misclassifications in some special cases and most others focus on assessing the accuracy of the diagnostic devices. In …
Nonparametric Tests Of Lack Of Fit For Multivariate Data, Yan Xu
Nonparametric Tests Of Lack Of Fit For Multivariate Data, Yan Xu
Theses and Dissertations--Statistics
A common problem in regression analysis (linear or nonlinear) is assessing the lack-of-fit. Existing methods make parametric or semi-parametric assumptions to model the conditional mean or covariance matrices. In this dissertation, we propose fully nonparametric methods that make only additive error assumptions. Our nonparametric approach relies on ideas from nonparametric smoothing to reduce the test of association (lack-of-fit) problem into a nonparametric multivariate analysis of variance. A major problem that arises in this approach is that the key assumptions of independence and constant covariance matrix among the groups will be violated. As a result, the standard asymptotic theory is not …