Efficient Estimation Of Risk Ratios From Clustered Binary Data,
2013
Harvard School of Public Health
Efficient Estimation Of Risk Ratios From Clustered Binary Data, Matthew Cefalu, Eric Tchetgen Tchetgen
Harvard University Biostatistics Working Paper Series
No abstract provided.
Extensions For The Epsilon Skew Exponential Power Distribution Family,
2013
University of Arkansas Little Rock
Extensions For The Epsilon Skew Exponential Power Distribution Family, Ahmad N. Flaih
Theses and Dissertations
Practical applied statistics reveals that the analysis of many real data that exhibit both fat-tailless and skewness shows significant departures from normality assumptions. In these circumstances, the adoption of more flexible models that cope with near normal data may be appropriate in place of adopting the robust approach, semi-parametric or nonparametric models, and Box-Cox transformation. An alternative approach is to consider using the Epsilon Skew Exponential Power (ESEP) distribution developed by Elsalloukh [12] and [15] which embeds the normal, fat-tailedness, and skewness distributions as special cases. We develop models based on using the ESEP family, in particular, the ESEP receiver …
Causes Of Death In Surgically Treated Patients With Type A Aortic Dissection - A Ten Year Review,
2013
Lehigh Valley Health Network
Causes Of Death In Surgically Treated Patients With Type A Aortic Dissection - A Ten Year Review, James K. Wu Md, Eilizabeth Depaolo Bs, Theodore G. Phillips Md, Timothy S. Misselbeck
Department of Surgery
No abstract provided.
The Net Reclassification Index (Nri): A Misleading Measure Of Prediction Improvement With Miscalibrated Or Overfit Models,
2013
University of Washington, Fred Hutch Cancer Research Center
The Net Reclassification Index (Nri): A Misleading Measure Of Prediction Improvement With Miscalibrated Or Overfit Models, Margaret Pepe, Jin Fang, Ziding Feng, Thomas Gerds, Jorgen Hilden
UW Biostatistics Working Paper Series
The Net Reclassification Index (NRI) is a very popular measure for evaluating the improvement in prediction performance gained by adding a marker to a set of baseline predictors. However, the statistical properties of this novel measure have not been explored in depth. We demonstrate the alarming result that the NRI statistic calculated on a large test dataset using risk models derived from a training set is likely to be positive even when the new marker has no predictive information. A related theoretical example is provided in which a miscalibrated risk model that includes an uninformative marker is proven to erroneously …
Simulation Insights Using R,
2013
CUNY New York City College of Technology
Simulation Insights Using R, Boyan Kostadinov
Publications and Research
This article attempts to introduce the reader to computational thinking and solving problems involving randomness. The main technique being employed is the Monte Carlo method, using the freely available software R for Statistical Computing. The author illustrates the computer simulation approach by focusing on several problems of increasing difficulty. The simulation techniques and the specific problems discussed in this article would be of interest to STEM students and instructors, teaching courses in Monte Carlo simulations, stochastic modeling, probability and statistics. The R code for all problems is discussed in full detail so that the reader can get a taste of …
Predicting Human Movement Type Based On Multiple Accelerometers Using Movelets,
2013
Johns Hopkins Bloomberg School of Public Health
Predicting Human Movement Type Based On Multiple Accelerometers Using Movelets, Bing He, Jiawei Bai, Annemarie Koster, Casserotti Paolo, Nancy Glynn, Tamara B. Harris, Ciprian Crainiceanu
Johns Hopkins University, Dept. of Biostatistics Working Papers
We introduce statistical methods for prediction of types of human movement based on three tri-axial accelerometers worn simultaneously at the hip, left, and right wrist. We compare the individual performance of the three accelerometers using movelets and propose a new prediction algorithm that integrates the information from all three accelerometers. The development is motivated by a study of 20 older subjects who were instructed to perform 15 different types of activities during in-laboratory sessions. The differences in the prediction performance for different activity types among the three accelerometers reveal subtle yet important insights into how the intrinsic physical features of …
Journal Acceptance Policies On Etds,
2013
California Polytechnic State University, San Luis Obispo
Is Obesity Socially Contagious?,
2013
California Polytechnic State University, San Luis Obispo
Is Obesity Socially Contagious?, Ciani Jean Sparks
Statistics
The main objective of this paper is to analyze three different articles that discuss whether obesity could be socially contagious. According to the World Health Organization in 2013, obesity is the fifth leading risk for deaths around the world. This disease has dramatically increased in the last decade, which has led scientists to believe there are other factors contributing to the epidemic besides genetics. The first article I analyzed, written by Nicholas Christakis and James Fowler, provided a logistic regression model to estimate the odds of a person becoming obese. The model included the explanatory variables: age, sex, education, smoking …
Immersed Finite Element Methods For Parabolic Equations With Moving Interface,
2013
Missouri University of Science and Technology
Immersed Finite Element Methods For Parabolic Equations With Moving Interface, Xiaoming He, Tao Lin, Yanping Lin, Xu Zhang
Mathematics and Statistics Faculty Research & Creative Works
This article presents three Crank-Nicolson-type immersed finite element (IFE) methods for solving parabolic equations whose diffusion coefficient is discontinuous across a time dependent interface. These methods can use a fixed mesh because IFEs can handle interface jump conditions without requiring the mesh to be aligned with the interface. These methods will be compared analytically in the sense of accuracy and computational cost. Numerical examples are provided to demonstrate features of these three IFE methods. © 2012 Wiley Periodicals, Inc.
Properties Of Higher-Order Half-Linear Functional Differential Equations With Noncanonical Operators,
2013
Missouri University of Science and Technology
Properties Of Higher-Order Half-Linear Functional Differential Equations With Noncanonical Operators, Chenghui Zhang, Ravi P. Agarwal, Martin Bohner, Tongxing Li
Mathematics and Statistics Faculty Research & Creative Works
Some new results are presented for the oscillatory and asymptotic behavior of higher-order half-linear differential equations with a noncanonical operator. We study the delayed and advanced equations subject to various conditions. © 2013 Zhang et al.
Views On Sexual Assault Among Ifc Fraternities,
2013
California Polytechnic State University, San Luis Obispo
Views On Sexual Assault Among Ifc Fraternities, Steven Legore
Statistics
The data collection and analysis for this project was performed for a consulting client Cierra, a fourth year Sociology major that works at the Safer Office on campus. She went to the consulting center on campus for help with the analysis of her project. She wanted to survey the IFC fraternities at Cal Poly on their views on sexual assault and rape. Thirteen IFC fraternities were surveyed with a total of 488 respondents. The responses to the 30 question True/False survey were used to evaluate the respondent’s empathy towards women, hostility towards women, and sexual aggression. Another research interest was …
Assessing The Impact Of Differential Genotyping Errors On Rare Variant Tests Of Association,
2013
Scripps College
Assessing The Impact Of Differential Genotyping Errors On Rare Variant Tests Of Association, Morgan Mayer-Jochimsen, Shannon Fast, Nathan L. Tintle
Faculty Work Comprehensive List
Genotyping errors are well-known to impact the power and type I error rate in single marker tests of association. Genotyping errors that happen according to the same process in cases and controls are known as non-differential genotyping errors, whereas genotyping errors that occur with different processes in the cases and controls are known as differential genotype errors. For single marker tests, non-differential genotyping errors reduce power, while differential genotyping errors increase the type I error rate. However, little is known about the behavior of the new generation of rare variant tests of association in the presence of genotyping errors. In …
A Bayesian Regression Tree Approach To Identify The Effect Of Nanoparticles Properties On Toxicity Profiles,
2013
UCLA Biostatistics - CNSI
A Bayesian Regression Tree Approach To Identify The Effect Of Nanoparticles Properties On Toxicity Profiles, Cecile Low-Kam, Haiyuan Zhang, Zhaoxia Ji, Tian Xia, Jeffrey I. Zinc, Andre Nel, Donatello Telesca
COBRA Preprint Series
We introduce a Bayesian multiple regression tree model to characterize relationships between physico-chemical properties of nanoparticles and their in-vitro toxicity over multiple doses and times of exposure. Unlike conventional models that rely on data summaries, our model solves the low sample size issue and avoids arbitrary loss of information by combining all measurements from a general exposure experiment across doses, times of exposure, and replicates. The proposed technique integrates Bayesian trees for modeling threshold effects and interactions, and penalized B-splines for dose and time-response surfaces smoothing. The resulting posterior distribution is sampled via a Markov Chain Monte Carlo algorithm. This …
A Graph-Theoretical Approach To The Selection Of The Minimum Tiling Path From A Physical Map,
2013
Marquette University
A Graph-Theoretical Approach To The Selection Of The Minimum Tiling Path From A Physical Map, Serdar Bozdag
Mathematics, Statistics and Computer Science Faculty Research and Publications
The problem of computing the minimum tiling path (MTP) from a set of clones arranged in a physical map is a cornerstone of hierarchical (clone-by-clone) genome sequencing projects. We formulate this problem in a graph theoretical framework, and then solve by a combination of minimum hitting set and minimum spanning tree algorithms. The tool implementing this strategy, called FMTP, shows improved performance compared to the widely used software FPC. When we execute FMTP and FPC on the same physical map, the MTP produced by FMTP covers a higher portion of the genome, and uses a smaller number of clones. For …
Rattus Model Utilizing Selective Pulmonary Ischemia Induces Bronchiolitis Obliterans Organizing Pneumonia,
2013
Medical College of Wisconsin
Rattus Model Utilizing Selective Pulmonary Ischemia Induces Bronchiolitis Obliterans Organizing Pneumonia, John C. Densmore, Paul M. Jeziorczak, Anne V. Clough, Kirkwood A. Pritchard Jr, Breana Cummens, Meetha Medhora, Arjun Rao, Elizabeth R. Jacobs
Mathematics, Statistics and Computer Science Faculty Research and Publications
Bronchiolitis obliterans organizing pneumonia (BOOP), a morbid condition when associated with lung transplant and chronic lung disease, is believed to be a complication of ischemia. Our goal was to develop a simple and reliable model of lung ischemia in the Sprague-Dawley rat that would produce BOOP. Unilateral ischemia without airway occlusion was produced by an occlusive slipknot placed around the left main pulmonary artery. Studies were performed 7 days later. Relative pulmonary and systemic flow to each lung was measured by injection of technetium Tc 99m macroaggregated albumin. Histological sections were examined for structure and necrosis and scored for BOOP. …
New Tools For Quantitative Decision Analysis In Applied Ecology And Conservation,
2013
University of Nebraska-Lincoln
New Tools For Quantitative Decision Analysis In Applied Ecology And Conservation, Adam W. Schapaugh
School of Natural Resources: Dissertations, Theses, and Student Research
Scientists have generated a massive body of theory aimed at predicting and managing the impacts of anthropogenic activities on populations, species, and ecosystems. Transforming this research into knowledge that informs complex decision-making problems remains a major challenge in environmental management and conservation. My dissertation research aims to address this issue through the development and application of mathematical and statistical models. I integrate tools, concepts, and techniques from ecology, applied mathematics, computer science, and statistics to build structured decision-making frameworks for spatial prioritization, resource allocation, and optimal scheduling. I also tackle several of the technical challenges limiting the utility of such …
Design, Implications And Analysis Of Household Survey: Practical Issues To Note,
2013
Central Bank of Nigeria
Design, Implications And Analysis Of Household Survey: Practical Issues To Note, O. O. Akanji
Bullion
This paper is to enhance the analytic processes of survey data as generated in the established household survey framework for economic policy management and decision making. The paper is divided into four sections. Section 1 is the introduction while Section 2 is the descriptive statistics emphasizing the models that bring out the relationship between the survey variables, Section 4 concludes and proffers recommendations.
Mind The Gaps,
2013
Marquette University
Mind The Gaps, Paul Bankston
Mathematics, Statistics and Computer Science Faculty Research and Publications
No abstract provided.
Asymptotic And Finite Sample Behavior Of Net Reclassification Indices,
2013
University of Washington - Seattle Campus
Asymptotic And Finite Sample Behavior Of Net Reclassification Indices, Zheyu Wang
UW Biostatistics Working Paper Series
The Net Reclassification Index (NRI) introduced by Pencina and colleagues [1, 2] is designed to quantify the prediction increment provided by a new biomarker. It has become popular for evaluating and selecting novel markers. The published variance formulae for NRI statistics do not account for the fact that risks are estimated based on risk models fit to data, and thus are not valid in practice when estimated risks are used [3]. Kerr and colleagues [4] showed that the confidence intervals constructed based on a bootstrap estimate of the variance and Normal approximation had the best performance among various methods they …
On The Restricted Mean Event Time In Survival Analysis,
2013
Stanford University School of Medicine
On The Restricted Mean Event Time In Survival Analysis, Lu Tian, Lihui Zhao, L. J. Wei
Harvard University Biostatistics Working Paper Series
No abstract provided.
