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Full-Text Articles in Physical Sciences and Mathematics
Statistical Inferences For The Youden Index, Haochuan Zhou
Statistical Inferences For The Youden Index, Haochuan Zhou
Mathematics Dissertations
In diagnostic test studies, one crucial task is to evaluate the diagnostic accuracy of a test. Currently, most studies focus on the Receiver Operating Characteristics Curve and the Area Under the Curve. On the other hand, the Youden index, widely applied in practice, is another comprehensive measurement for the performance of a diagnostic test. For a continuous-scale test classifying diseased and non-diseased groups, finding the Youden index of the test is equivalent to maximize the sum of sensitivity and specificity for all the possible values of the cut-point. This dissertation concentrates on statistical inferences for the Youden index. First, an …
Assessment Of Watershed Model Simplification And Potential Application In Small Ungaged Watersheds: A Case Study Of Big Creek, Atlanta, Ga, Zoia A. Comarova Ms
Assessment Of Watershed Model Simplification And Potential Application In Small Ungaged Watersheds: A Case Study Of Big Creek, Atlanta, Ga, Zoia A. Comarova Ms
Geosciences Theses
Technological and methodological advances of the past few decades have provided hydrologists with advanced and increasingly complex hydrological models. These models improve our ability to simulate hydrological systems, but they also require a lot of detailed input data and, therefore, have a limited applicability in locations with poor data availability. From a case study of Big Creek watershed, a 186.4 km2 urbanizing watershed in Atlanta, GA, for which continuous flow data are available since 1960, this project investigates the relationship between model complexity, data availability and predictive performance in order to provide reliability factors for the use of reduced …
Testing An Assumption Of Non-Differential Misclassification In Case-Control Studies, Qin Hui
Testing An Assumption Of Non-Differential Misclassification In Case-Control Studies, Qin Hui
Mathematics Theses
One of the issues regarding the misclassification in case-control studies is whether the misclassification error rates are the same for both cases and controls. Currently, a common practice is to assume that the rates are the same (“non-differential” assumption). However, it is suspicious that this assumption is valid in many case-control studies. Unfortunately, no test is available so far to test the validity of the assumption of non-differential misclassification when the validation data are not available. We propose the first such method to test the validity of non-differential assumption in a case-control study with 2 × 2 contingency table. First, …