Statistics and Probability Commons^™

A Meta-Analysis Of The Effects Of Incentives On Response Rate In Online Survey Studies, Amal Muhammad Asire

Electronic Theses and Dissertations

Meta-analysis was used to investigate the effect of incentives on response rates of web-based survey studies. Whereas numerous meta-analyses that address the effect of incentives on increasing response rates in survey studies are available in the literature, these analyses are based on mail surveys, so there is a need for an applied meta-analysis to examine the effect of incentives on response rates in online survey studies. A meta-analysis of an online method of survey administration was used because the use of online surveys has greatly increased, making web-based survey administration an important form of data collection in multiple fields of …

Statistical Modeling Of The Default Mode Brain Network Reveals A Segregated Highway Structure, P. E. Stillman, James D. Wilson, M. J. Denny, B. A. Desmarais, Shankar Bhamidi, S. J. Cranmer, Zhong-Lin Lu

Mathematics

We investigate the functional organization of the Default Mode Network (DMN) – an important subnetwork within the brain associated with a wide range of higher-order cognitive functions. While past work has shown the whole-brain network of functional connectivity follows small-world organizational principles, subnetwork structure is less well understood. Current statistical tools, however, are not suited to quantifying the operating characteristics of functional networks as they often require threshold censoring of information and do not allow for inferential testing of the role that local processes play in determining network structure. Here, we develop the correlation Generalized Exponential Random Graph Model (cGERGM) …

The In Vivo Effect Of Oil Palm Phenolics (Opp) In Atherogenic Diet Induced Rats Model Of Alzheimer’S Disease (Ad), Yan Wu

Wayne State University Dissertations

Alzheimer’s disease (AD) is the most common cause of dementia in the aging population. It is characterized by cognitive decline and deposition of ß-amyloid plaques in the hippocampus. It has been shown that hypercholesterolemia induced by high cholesterol diet is associated with AD development. Increased level of oxidative stress has also been observed in AD patients. An important strategy to treat or delay the impairment is based on dietary modification, using food supplements. OPP, a water soluble fraction from oil palm fruit, rich in phenolics has been found to possess significant antioxidant activities. Its beneficial effects on cardiovascular diseases, diabetes …

Quantum Foundations With Astronomical Photons, Calvin Leung

HMC Senior Theses

Bell's inequalities impose an upper limit on correlations between measurements of two-photon states under the assumption that the photons play by a set of local rules rather than by quantum mechanics. Quantum theory and decades of experiments both violate this limit.

Recent theoretical work in quantum foundations has demonstrated that a local realist model can explain the non-local correlations observed in experimental tests of Bell's inequality if the underlying probability distribution of the local hidden variable depends on the choice of measurement basis, or ``setting choice''. By using setting choices determined by astrophysical events in the distant past, it is …

Assessing Very Early Infant Diagnosis Turnaround Times: Findings From A Birth Testing Pilot In Lesotho, Michelle Gill, Heather J. Hoffman, Majoalane Mokone, Vincent Tukei, Matsepeli Nchephe, +Several Additional Authors

Epidemiology Faculty Publications

Very early infant diagnosis (VEID) (testing within two weeks of life), combined with rapid treatment initiation, could reduce early infant mortality. Our study evaluated turnaround time (TAT) to receipt of infants’ HIV test results and ART initiation if HIV-infected, with and without birth testing availability. Data from facility records and national databases were collected for 12 facilities offering VEID, as part of an observational prospective cohort study, and 10 noncohort facilities. HIV-exposed infants born in January–June 2016 and any cohort infant diagnosed as HIV-infected at birth or six weeks were included. The median TAT from blood draw to caregiver result …

Risk Of Gastrointestinal Bleeding Among Dabigatran Users – A Self Controlled Case Series Analysis, Wenze Tang, Hsien-Yen Chang, Meijia Zhou, Sonal Singh

Epidemiology Faculty Publications

This article aims to evaluate the real world risk of gastrointestinal bleeding among users naïve to dabigatran. We adopted a self-controlled case series design. We sampled 1215 eligible adult participants who were continuous insured users between July 1, 2010 and March 31, 2012 with use of dabigatran and at least one gastrointestinal bleeding episode. We used a conditional Poisson regression to estimate incidence rate ratios. The population consisted of 64.69% of male and 60.25% patients equal to or greater than age 65 at start of observation. After adjustment for time-variant confounders, the incidence rate of gastrointestinal bleeding was similar during …

Post-Diagnosis Body Mass Index And Mortality Among Women Diagnosed With Endometrial Cancer: Results From The Women's Health Initiative., Hannah Arem, Ruth M Pfeiffer, Steven C Moore, Melinda L Irwin, Michael J Lamonte, Gloria E Sarto, Rami Nassir, Juhua Luo, Rowan T Chlebowski, Louise A Brinton, Charles E Matthews

Epidemiology Faculty Publications

Higher body mass index (BMI) measured before endometrial cancer diagnosis has been associated with greater risk of developing endometrial cancer and higher mortality, but the association between BMI measured after diagnosis and mortality risk is unclear. We identified 467 women (91 deaths) in the Women's Health Initiative (WHI) with information on BMI measured after diagnosis and used Cox proportional hazards regression to generate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause mortality. Comparing BMI 35+ with/m2, we observed no association with all-cause mortality (HR = 1.02, 95% CI 0.55-1.91). Our study does not support the hypothesis that higher …

Meta-Analyses Of The Relationship Between Depression And Nine Dimensions Of Perfectionism, Gabriel Lynn Hottinger

Electronic Theses and Dissertations

Perfectionism has been shown to be related to depression, but perfectionism is multidimensional. Some dimensions are related to positive psychological characteristics and outcomes and other dimensions are related to negative psychological characteristics and outcomes. This study reports results of nine meta-analyses performed to investigate the association between each of nine subscales of perfectionism and depression to determine which dimensions of perfectionism are most strongly associated with depression. The two subscales that were used from the Hewitt and Flett (1991b) Multidimensional Perfectionism scale were Self-Oriented Perfectionism (SOP) and Socially-Prescribed Perfectionism (SPP). The five subscales that were used from the Frost et …

Case Study For Guided Project In Stochastic Hydrology, Meghna Babbar-Sebens

All ECSTATIC Materials

Attached are two guided project activities for hydrology and climate data of Eagle Creek Watershed, Indiana, USA. The zip files have flow and precipitation datasets at daily, monthly, and annual time scales.

Kinetic Monte Carlo Methods For Computing First Capture Time Distributions In Models Of Diffusive Absorption, Daniel Schmidt

HMC Senior Theses

In this paper, we consider the capture dynamics of a particle undergoing a random walk above a sheet of absorbing traps. In particular, we seek to characterize the distribution in time from when the particle is released to when it is absorbed. This problem is motivated by the study of lymphocytes in the human blood stream; for a particle near the surface of a lymphocyte, how long will it take for the particle to be captured? We model this problem as a diffusive process with a mixture of reflecting and absorbing boundary conditions. The model is analyzed from two approaches. …

The Document Similarity Network: A Novel Technique For Visualizing Relationships In Text Corpora, Dylan Baker

HMC Senior Theses

With the abundance of written information available online, it is useful to be able to automatically synthesize and extract meaningful information from text corpora. We present a unique method for visualizing relationships between documents in a text corpus. By using Latent Dirichlet Allocation to extract topics from the corpus, we create a graph whose nodes represent individual documents and whose edge weights indicate the distance between topic distributions in documents. These edge lengths are then scaled using multidimensional scaling techniques, such that more similar documents are clustered together. Applying this method to several datasets, we demonstrate that these graphs are …

Machine Learning On Statistical Manifold, Bo Zhang

HMC Senior Theses

This senior thesis project explores and generalizes some fundamental machine learning algorithms from the Euclidean space to the statistical manifold, an abstract space in which each point is a probability distribution. In this thesis, we adapt the optimal separating hyperplane, the k-means clustering method, and the hierarchical clustering method for classifying and clustering probability distributions. In these modifications, we use the statistical distances as a measure of the dissimilarity between objects. We describe a situation where the clustering of probability distributions is needed and useful. We present many interesting and promising empirical clustering results, which demonstrate the statistical-distance-based clustering algorithms …

05. Table Of Contents - Design And Analysis Of Experiments, Angela Dean, Dan Voss, Danel Draguljic

Design and Analysis of Experiments

The table of content of Design and Analysis of Experiments.

04. Chapters - Design And Analysis Of Experiments, Angela Dean, Dan Voss, Danel Draguljic

Design and Analysis of Experiments

A list of the chapters from Design and Analysis of Experiments.

02. Preface Of Design And Analysis Of Experiments - 2nd Edition, Angela Dean, Dan Voss, Danel Draguljic

Design and Analysis of Experiments

Preface of the second edition of Design and Analysis of Experiments.

09. R Data Files For Design And Analysis Of Experiments, Angela Dean, Dan Voss, Danel Draguljic

Design and Analysis of Experiments

R Data files for Design and Analysis of Experiments.

Statin Use And Risk Of Developing Diabetes: Results From The Diabetes Prevention Program, Diabetes Prevention Program(Dpp) Research Group, Marinella G. Temprosa

GW Biostatistics Center

Objective Several clinical trials of cardiovascular disease prevention with statins have reported increased risk of type 2 diabetes (T2DM) with statin therapy. However, participants in these studies were at relatively low risk for diabetes. Further, diabetes was often based on self-report and was not the primary outcome. It is unknown whether statins similarly modify diabetes risk in higher risk populations.

Research design and methods During the Diabetes Prevention Program Outcomes Study (n=3234), the long-term follow-up to a randomized clinical trial of interventions to prevent T2DM, incident diabetes was assessed by annual 75 g oral glucose tolerance testing and semiannual fasting …

Anti-Müllerian Hormone And Its Relationships With Subclinical Cardiovascular Disease And Renal Disease In A Longitudinal Cohort Study Of Women With Type 1 Diabetes, Catherine Kim, Yuanyuan Pan, Barbara Braffett, Valerie Arends, Michael Steffes, Hunter Wessells, Aruna V. Sarma

GW Biostatistics Center

Background

Reproductive age may be a risk factor for vascular disease. Anti-Müllerian hormone (AMH) is produced by viable ovarian follicles and reflects reproductive age. We examined whether AMH concentrations were associated with markers of subclinical cardiovascular disease (CVD) and kidney disease among women with type 1 diabetes.

Methods

We performed a cross-sectional analysis of the Epidemiology of Diabetes Interventions and Complications Study. Participants included women with type 1 diabetes and ≥1 AMH measurement (n = 390). In multivariable regression models which adjusted for repeated measures, we examined the associations between AMH with CVD risk factors, estimated glomerular filtration rate, …

A Study Of Mathematics Achievement, Placement, And Graduation Of Engineering Students, Sara Hahler Blazek

Doctoral Dissertations

The purpose of this study was to determine how background knowledge impacts freshmen engineering students' success at Louisiana Tech University in terms of grades in two different freshman classes and graduation. To determine what factors impact students, three different studies were implemented. The first study used linear regression to analyze which demographic and academic variables significantly impacted freshman math and engineering courses. Using regression discontinuity, the second study determined if the university's placement requirement for Pre-Calculus was appropriate. The final study analyzed factors that impact graduation for engineering students as well as other disciplines to determine which significant variables were …

Biomarkers Of Tubulointerstitial Damage And Function In Type 1 Diabetes, Ian De Boer, Xiaoyu Gao, Ionut Bebu, Andrew Hoofnagle, John Lachin, Diabetes Control And Complications Trial/Epidemiology Of Diabetes Interventions And Complications (Dcct/Edic) Research Group.

Epidemiology Faculty Publications

Objective To evaluate biomarkers of renal tubulointerstitial damage and function in type 1 diabetes with and without diabetic kidney disease.

Research design and methods Cross-sectional case-control study of Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study participants. Cases (N=43) had incident persistent estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 with urinary albumin excretion >300 mg/24 hour. Controls (N=43) had persistent eGFR >90 mL/min/1.73 m2 and urinary albumin excretion <30 mg/24 hour. Urinary and plasma biomarkers reflecting tubular injury, inflammation, fibrosis, secretion, and synthetic function were measured from stored specimens collected at the first study visit with reduced eGFR (for case participants) or the corresponding study year (for control participants).

Results Mean (SD) age was 51 (9) and 50 (8) years for case and control participants, and mean (SD) duration of diabetes was 30 (6) and 30 (5) years, respectively. Mean (SD) eGFR was 39 …

Perspectives On Model Forecasts Of The 2014–2015 Ebola Epidemic In West Africa: Lessons And The Way Forward, Gerardo Chowell, Cecile Viboud, Lone Simonsen, Stefano Merler, Alessandro Vespignani

Global Health Faculty Publications

The unprecedented impact and modeling efforts associated with the 2014–2015 Ebola epidemic in West Africa provides a unique opportunity to document the performances and caveats of forecasting approaches used in near-real time for generating evidence and to guide policy. A number of international academic groups have developed and parameterized mathematical models of disease spread to forecast the trajectory of the outbreak. These modeling efforts often relied on limited epidemiological data to derive key transmission and severity parameters, which are needed to calibrate mechanistic models. Here, we provide a perspective on some of the challenges and lessons drawn from these efforts, …

When Is A Randomised Controlled Trial Health Equity Relevant? Development And Validation Of A Conceptual Framework, J. Jull, M. Whitehead, M. Petticrew, E. Kristjansson, D. Gough, Sarah Baird, +Several Additional Authors

Global Health Faculty Publications

Background Randomised controlled trials can provide evidence relevant to assessing the equity impact of an intervention, but such information is often poorly reported. We describe a conceptual framework to identify health equity-relevant randomised trials with the aim of improving the design and reporting of such trials.

Methods An interdisciplinary and international research team engaged in an iterative consensus building process to develop and refine the conceptual framework via face-to-face meetings, teleconferences and email correspondence, including findings from a validation exercise whereby two independent reviewers used the emerging framework to classify a sample of randomised trials.

Results A randomised trial can …

Logistic Ensemble Models, Bob Vanderheyden, Jennifer L. Priestley

Published and Grey Literature from PhD Candidates

Predictive models that are developed in a regulated industry or a regulated application, like determination of credit worthiness must be interpretable and “rational” (e.g., improvements in basic credit behavior must result in improved credit worthiness scores). Machine Learning technologies provide very good performance with minimal analyst intervention, so they are well suited to a high volume analytic environment but the majority are “black box” tools that provide very limited insight or interpretability into key drivers of model performance or predicted model output values. This paper presents a methodology that blends one of the most popular predictive statistical modeling methods with …

Detecting Discordance Enrichment Among A Series Of Two-Sample Genome-Wide Expression Data Sets, Yinglei Lai, Fanni Zhang, Tapan Nayak, Reza Modarres, Norman H. Lee, Timothy A. Mccaffrey

Epidemiology Faculty Publications

Background

With the current microarray and RNA-seq technologies, two-sample genome-wide expression data have been widely collected in biological and medical studies. The related differential expression analysis and gene set enrichment analysis have been frequently conducted. Integrative analysis can be conducted when multiple data sets are available. In practice, discordant molecular behaviors among a series of data sets can be of biological and clinical interest.

Methods

In this study, a statistical method is proposed for detecting discordance gene set enrichment. Our method is based on a two-level multivariate normal mixture model. It is statistically efficient with linearly increased parameter space when …

Willingness Of Community-Recruited Men Who Have Sex With Men In Washington, Dc To Use Long-Acting Injectable Hiv Pre-Exposure Prophylaxis., Matthew E Levy, Rudy Patrick, Jonjelyn Gamble, Anthony Rawls, Jenevieve Opoku, Manya Magnus, Michael Kharfen, Alan E Greenberg, Irene Kuo

Epidemiology Faculty Publications

Objectives

Clinical trials are currently investigating the safety and efficacy of long-acting injectable (LAI) agents as HIV pre-exposure prophylaxis (PrEP). Using National HIV Behavioral Surveillance data, we assessed the self-reported willingness of men who have sex with men (MSM) to use LAI PrEP and their preference for LAI versus daily oral PrEP.

Methods

In 2014, venue-based sampling was used to recruit MSM aged ≥18 years in Washington, DC. Participants completed an interviewer-administered survey followed by voluntary HIV testing. This analysis included MSM who self-reported negative/unknown HIV status at study entry. Correlates of being “very likely” to use LAI PrEP and …

What’S Brewing? A Statistics Education Discovery Project, Marla A. Sole, Sharon L. Weinberg

Publications and Research

We believe that students learn best, are actively engaged, and are genuinely interested when working on real-world problems. This can be done by giving students the opportunity to work collaboratively on projects that investigate authentic, familiar problems. This article shares one such project that was used in an introductory statistics course. We describe the steps taken to investigate why customers are charged more for iced coffee than hot coffee, which included collecting data and using descriptive and inferential statistical analysis. Interspersed throughout the article, we describe strategies that can help teachers implement the project and scaffold material to assist students …

Stochastic Processes And Integrals, Jose L. Menaldi

Mathematics Faculty Research Publications

Stochastic integrals with respect to Wiener process and Poisson measures are discusses, beginning from stochastic processes.

Barriers To Counseling Among Human Service Professionals: The Development And Validation Of The Fit, Stigma, & Value Scale, Edward S. Neukrug, Michael T. Kalkbrenner, Sandy-Ann M. Griffith

Counseling & Human Services Faculty Publications

This study sought to confirm rates of attendance in counseling of human service professionals and validate a 32-item questionnaire designed to identify barriers to counseling seeking behavior among this population. Results indicated that a large percentage of human service professionals attend counseling, with males and females attending at similar rates and non-Caucasians attending at lower rates. A multivariate analysis of variance and descriptive statistics identified the most common barriers to attendance in counseling and examined demographic differences in participants’ sensitivity towards barriers to attendance in counseling. A Principal Factor Analysis (PFA) revealed three subscales (fit, value, and stigma), which we …

Flow Conditions In The Intracranial Aneurysm Lumen Are Associated With Inflammation And Degenerative Changes Of The Aneurysm Wall, J. Cebral, E. Ollikainen, Bong Jae Chung, F. Mut, V. Sippola, B. R. Jahromi, R. Tulamo, J. Hernesniemi, M. Niemelä, A. Robertson, J. Frösen

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

BACKGROUND AND PURPOSE: Saccular intracranial aneurysm is a common disease that may cause devastating intracranial hemorrhage. Hemodynamics, wall remodeling, and wall inflammation have been associated with saccular intracranial aneurysm rupture.Weinvestigated how saccular intracranial aneurysm hemodynamics is associated with wall remodeling and inflammation of the saccular intracranial aneurysm wall. MATERIALS AND METHODS: Tissue samples resected during a saccular intracranial aneurysm operation (11 unruptured, 9 ruptured) were studied with histology and immunohistochemistry. Patient-specific computational models of hemodynamics were created from preoperative CT angiographies. RESULTS: More stable and less complex flows were associated with thick, hyperplastic saccular intracranial aneurysm walls, while slower flows …

Examining The Activities, Effectiveness, And Contribution Of Local Health Departments Using A National Longitudinal Survey Of Public Health Systems, Lava R. Timsina

Theses and Dissertations--Epidemiology and Biostatistics

Health services research and public health services and systems research in the past have contributed to a strong foundation of evidence-based progress in organizing, financing, and delivering medical care and public health strategies across the United States. The purpose of this dissertation was to examine disparities in public health systems and in the delivery of population health services in communities served by these systems using nationally representative data from the National Longitudinal Survey of Local Public Health Systems (1998, 2006, 2012, and 2014).

Data from the 1998 cohort of 497 local health jurisdictions serving at least 100,000 residents, and from …