Statistics and Probability Commons^™

Four Weeks Of Minimalist Style Running Training Reduced Lumbar Paraspinal Muscle Activation During Shod Running, Stephanie Barton, David Brown, Talia Joyce

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background and Purpose: Research has shown that the risk of low back dysfunctions in runners is related to the increased mileage of distance running. Repetitive shock loading of the spinal structures during running has been indicated as one of the important biomechanical mechanisms underlying such injury. Acute changes in foot strike pattern, like those seen during minimalist style running, have been shown to lead to modifications in lumbar range of motion. Minimalist style running could lead to changes in lumbar biomechanics and muscle activation, potentially reducing the loading on the musculoskeletal structures of the lower back. However, the long term …

Exact Statistical Inferences For Functions Of Parameters Of The Log-Gamma Distribution, Joseph F. Mcdonald

UNLV Theses, Dissertations, Professional Papers, and Capstones

The log-gamma model has been used extensively for flood frequency analysis and is an important distribution in reliability, medical and other areas of lifetime testing. Conventional methods fails to provide exact solutions for the log-gamma model while asymptotic methods provide approximate solutions that often have poor performance for typical sample sizes. The two parameter log-gamma distribution is examined using the generalized p-value approach. The methods are exact in the sense that the tests and the confidence intervals are based on exact probability statements rather than on asymptotic approximations. Exact tests and exact confidence intervals for the parameter of interest based …

A Study Of Sequential Inference For The Risk Ratio And Measure Of Reduction Of Two Binomials, Zhou Wang

UNLV Theses, Dissertations, Professional Papers, and Capstones

The binomial distribution is one of the most commonly and widely occurring probabilistic phenomena in our lives. Since observations from independent Bernoulli trials yield a dichotomous type, the distribution of sequences provides the basis and clue for statistical formulations of a wide variety of problems.

Occasionally, the core of biomedical studies is related to the comparison and evaluation of the risks of events or outcomes of interest in comparing populations under study. For instance, one wishes to compare two groups of subjects drawn from two independent populations. Then, two sample proportions play central roles in those comparisons. One of the …

Failing To Replicate: Hypothesis Testing As A Crucial Key To Make Direct Replications More Credible And Predictable, Pedro Fernando Mateu Bullón

Dissertations

Theory cannot be fully validated unless the original results have been replicated, resulting in conclusion consistency. Replications are the strongest source to verify research findings and knowledge claims. Sciences such as medicine, chemistry, physics, genetics, and biology, are considered successful because their knowledge claims are buttressed by a large set of replications of original studies. Unfortunately in the social sciences many attempts to replicate fail and thus there is a continuing need for replication studies to confirm facts, expand knowledge to gain new understanding, and verify hypotheses. Two plausible explanations for the failure to replicate in the social sciences could …

Three Essays On Panel Data Estimation, Alexander Houser

Dissertations

This work discusses various aspects of panel data estimation. In chapter one, an algorithm for semiparametric random effects estimation is proposed. The performance of bootstrap-based confidence intervals for the proposed estimators are examined and found reasonable. The algorithm is also applied to a set of U.S. state level medical expenditure data to estimate the medical Engel curve. In the second chapter, the predictive performance of various parametric and semiparametric panel data estimators is compared on the same dataset of U.S. state level medical expenditures as well as out of sample forecast performance and bootstrap bias-corrected mean square errors of the …

Patient No-Show For Outpatient Physical Therapy: A National Survey, James Bokinskie, Payton Johnson, Trevor Mahoney

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Patients who fail to show for scheduled medical appointments (no-show) create a cascade of issues for the health care system, the provider, and themselves. No-show can affect clinical productivity, cost and quality of care, and treatment outcomes. There is an overwhelming lack of research on no-show as it relates to outpatient physical therapy in the United States. The purposes of this study were to report national no-show rates, describe the presence and characteristics of no-show policies, determine the relationship of these policies and other demographic information to no-show rates, and describe the most commonly perceived reasons for no-show.

Methods: …

Immediate Effects Of Cervical Spine Manipulation On Gait Parameters In Individuals With And Without Mechanical Neck Pain, Jordan Isom, Shaylyn Kennedy, Justin May, Samuel Moore

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: The purpose of this study was to determine 1) if there were any differences in gait parameters between participants with mechanical neck pain and those without and 2) if cervical spine manipulation has an immediate effect on these gait parameters.

Methods: Twenty participants with mechanical neck pain and twenty participants without neck pain were randomly assigned into either the sham or manipulation group. The two intervention groups participated in walking across a GAITRite Walkway that recorded gait parameters such as stride length, cadence and step width before and after cervical spine manipulation. The participants walked at their own cadence …

The Immediate Effects Of Cervicothoracic Manipulation Versus Stretching On Upper Trapezius Pressure Pain Thresholds And Range Of Motion In Individuals Without Neck Pain, Kevin Carr, Morgan King, Erin Oelklaus, Brendan Parry

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background and Purpose: Myofascial pain may be considered one of the most common clinical findings in patients with neck pain (NP). Motor aspects of myofascial pain include disturbed motor function and muscle weakness secondary to motor inhibition, muscle stiffness, and restricted range of motion (ROM). Currently, it is unclear which interventions may have the greatest immediate impact on pressure pain sensitivity and ROM. Several studies have demonstrated improved pressure pain thresholds (PPT) after cervical manipulation; however, it is not clear if manipulation targeted to the cervicothoracic (CT) junction will have a similar effect. Others recommend stretching as a method to …

Annotation Tools For Multivariate Gene Set Testing Of Non-Model Organisms, Russell K. Banks

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microarray chip technology enables researchers to obtain measures of gene activity for essentially all genes in an organism. After grouping genes into biologically meaningful sets, researchers employ certain statistical tests to identify which gene sets (biological processes) show different levels of activity across different treatment groups. The idea is to identify which biological processes are significantly affected by a certain treatment/condition in a given organism.

Non-model organisms (such as sheep) are not widely studied so gene set membership information is not always readily accessible. This thesis work utilizes two microarray studies involving sheep to provide researchers with working examples of …

Scientific Awareness At Ursinus College, Frank G. Devone

Mathematics Honors Papers

Ursinus College prides itself on creating well-rounded students, and recent initiatives, such as the Fellowships in the Ursinus Transition to the Undergraduate Research Experience Program and the Center for Science and the Common Good suggest that science is a vital part of the Ursinus liberal arts mission. A scientific awareness pilot survey was administered to a sample of Ursinus students drawn from the Class of 2014 and students residing at Ursinus during summer 2014. Experience and data collected from this pilot were used to create a final survey which was made available to all students at Ursinus College. The survey …

Orbital Simulations For Directed Energy Deflection Of Near-Earth Asteroids, Qicheng Zhang, Kevin J. Walsh, Carl Melis, Gary B. Hughes, Philip Lubin

Statistics

Directed energy laser ablation at the surface of an asteroid or comet produces an ejection plume that will impart a thrust on the asteroid. This thrust can mitigate a threatened collision with the Earth. This technique uses the asteroid itself as the deflection propellant. The DESTAR laser system is designed to produce a sufficiently intense spot on the surface of an asteroid to accomplish this in one of two operational modes. One is a complete "stand-off" mode where a large space based phased-array laser directed energy system can interdict asteroids at large distances allowing sufficient time to mitigate nearly all …

Modeling Traffic At An Intersection, Kaleigh L. Mulkey, Saniita K. Fasenntao

Symposium of Student Scholars

The main purpose of this project is to build a mathematical model for traffic at a busy intersection. We use elements of Queueing Theory to build our model: the vehicles driving into the intersection are the “arrival process” and the stop light in the intersection is the “server.”

We collected traffic data on the number of vehicles arriving to the intersection, the duration of green and red lights, and the number of vehicles going through the intersection during a green light. We built a SAS macro code to simulate traffic based on parameters derived from the data.

In our program …

Adaptive Enrichment Designs For Randomized Trials With Delayed Endpoints, Using Locally Efficient Estimators To Improve Precision, Michael Rosenblum, Tianchen Qian, Yu Du, Huitong Qiu

Johns Hopkins University, Dept. of Biostatistics Working Papers

Adaptive enrichment designs involve preplanned rules for modifying enrollment criteria based on accrued data in an ongoing trial. For example, enrollment of a subpopulation where there is sufficient evidence of treatment efficacy, futility, or harm could be stopped, while enrollment for the remaining subpopulations is continued. Most existing methods for constructing adaptive enrichment designs are limited to situations where patient outcomes are observed soon after enrollment. This is a major barrier to the use of such designs in practice, since for many diseases the outcome of most clinical importance does not occur shortly after enrollment. We propose a new class …

Ranked Based Procedures For Ordered Alternative Models, Yuanyuan Shao

Research and Creative Activities Poster Day

The ordered alternatives in a one-way layout with k ordered treatment levels are appropriate for many applications, especially in psychology and medicine. There is an extensive literature in this area, and many parametric and nonparametric approaches have been introduced. This study uses rank based estimators to robustify the Abelson-Tukey method. The approach extends to the two-way layout with b blocks and k treatments. One of the two statistics having maximum asymptotic local power and the greatest efficiency when the alternative hypothesis consists of a specific pattern, and extended research has been completed on detecting ordered alternatives with unknown peaks.

Model Of Cost-Effectiveness Of Mri For Women Of Average Lifetime Risk Of Breast Cancer, Mckenna L. Kimball

Scholarly and Creative Works Conference (2015 - 2021)

Background: Mammography is the current standard for breast cancer detection however magnetic resonance imaging (MRI) is a more sensitive method of breast imaging. Despite MRI’s increased sensitivity, MRI has more false positives and higher costs. The purpose of this study was to determine if MRI or MRI in conjunction with mammography was a cost-effective solution for breast cancer detection in women with average lifetime risk of breast cancer.

Methods: A mathematical model was used to compare annual mammography, annual MRI, and mammography and MRI on alternate years. The model included the natural history of breast cancer, screening by mammography …

Characteristics Of Stem Success: A Survival Analysis Model Of Factors Influencing Time To Graduation Among Undergraduate Stem Majors, Riley K. Acton

Business and Economics Honors Papers

Producing more graduates in Science, Technology, Engineering, and Mathematics (STEM), as well as ensuring students complete college in a timely manner are both areas of national public policy interest. In order to improve these two outcomes, it is imperative to understand what factors lead undergraduate students to persist in, and ultimately graduate with STEM degrees. This paper uses data from the Beginning Postsecondary Students Longitudinal Study, provided by The National Center of Education Statistics, to model the time to baccalaureate degree among STEM majors using a Cox proportional hazard model.

Quantifying The Sensitivity Of Maximum, Limiting, And Potential Tropical Cyclone Intensity To Sst: Observations Versus The Fsu/ Coaps Global Climate Model, Sarah Strazzo, James Elsner, Tim Larow

Publications

No abstract provided.

Recent Periods Of Financial Turbulence On The Russian Stock Market And Their Effect On Price Correlation And Value At Risk, Alexander Logoveev, Gregory Cherinko

Undergraduate Economic Review

The aim of this article is to observe and analyze the recent periods of financial turbulence on the Russian stock market and determine their influence on the correlation coefficients between asset prices and the Value at Risk measure for a portfolio. Our task was to describe the previously observed phenomenon of correlation enlargement during times of financial crises deemed in our research as separate Black Swans. Based on up-to-date financial data analysis we determined correlation trends that can be useful in risk management and applied the Value at Risk method.

Simulation Of Semicompeting Risk Survival Data And Estimation Based On Multistate Frailty Model, Fei Jiang, Sebastien Haneuse

Harvard University Biostatistics Working Paper Series

We develop a simulation procedure to simulate the semicompeting risk survival data. In addition, we introduce an EM algorithm and a B–spline based estimation procedure to evaluate and implement Xu et al. (2010)’s nonparametric likelihood es- timation approach. The simulation procedure provides a route to simulate samples from the likelihood introduced in Xu et al. (2010)’s. Further, the EM algorithm and the B–spline methods stabilize the estimation and gives accurate estimation results. We illustrate the simulation and the estimation procedure with simluation examples and real data analysis.

Association Between Nutritional Awareness And Diet Quality: Evidence From The Observation Of Cardiovascular Risk Factors In Luxembourg (Oriscav-Lux) Study, Ala'a Alkerwi, Nicolas Sauvageot, Leoné Malan, Nitin Shivappa, James R. Hébert

Faculty Publications

This study examined the association between nutritional awareness and diet quality, as indicated by energy density, dietary diversity and adequacy to achieve dietary recommendations, while considering the potentially important role of socioeconomic status (SES). Data were derived from 1351 subjects, aged 18–69 years and enrolled in the ORISCAV-LUX study. Energy density score (EDS), dietary diversity score (DDS) and Recommendation Compliance Index (RCI) were calculated based on data derived from a food frequency questionnaire. Nutritional awareness was defined as self-perception of the importance assigned to eating balanced meals, and classified as high, moderate, or of little importance. Initially, a General Linear …

Gaussian Process Modeling Of Modern Mass Spectrometry Computer Experimental Data, Mickey Warner, C. Shane Reese

Journal of Undergraduate Research

Introduction A new mass spectrometry technique (VENDAMS) has been developed to allow the quantification of rate constants for complicated chemical reactions. Due to the expensive nature of the method, computer experiments designed to solve a set of equations provide supplemental information to the process.

Test On Existence Of Histology Subtype-Specific Prognostic Signatures Among Early Stage Lung Adenocarcinoma And Squamous Cell Carcinoma Patients Using A Cox-Model Based Filter, Suyan Tian, Chi Wang, Ming-Wen An

Biostatistics Faculty Publications

BACKGROUND: Non-small cell lung cancer (NSCLC) is the predominant histological type of lung cancer, accounting for up to 85% of cases. Disease stage is commonly used to determine adjuvant treatment eligibility of NSCLC patients, however, it is an imprecise predictor of the prognosis of an individual patient. Currently, many researchers resort to microarray technology for identifying relevant genetic prognostic markers, with particular attention on trimming or extending a Cox regression model. Adenocarcinoma (AC) and squamous cell carcinoma (SCC) are two major histology subtypes of NSCLC. It has been demonstrated that fundamental differences exist in their underlying mechanisms, which motivated us …

Impact Of Population Stratification On Family-Based Association In An Admixed Population, T. B. Mersha, L. Ding, H. He, E. S. Alexander, X. Zhang, B. G. Kurowski, V. Pilipenko, L. Kottyan, L. J. Martin, David W. Fardo

Biostatistics Faculty Publications

Population substructure is a well-known confounder in population-based case-control genetic studies, but its impact in family-based studies is unclear. We performed population substructure analysis using extended families of admixed population to evaluate power and Type I error in an association study framework. Our analysis shows that power was improved by 1.5% after principal components adjustment. Type I error was also reduced by 2.2% after adjusting for family substratification. The presence of population substructure was underscored by discriminant analysis, in which over 92% of individuals were correctly assigned to their actual family using only 100 principal components. This study demonstrates the …

Bootstrapping Vs. Asymptotic Theory In Property And Casualty Loss Reserving, Andrew J. Difronzo Jr.

Honors Projects in Mathematics

One of the key functions of a property and casualty (P&C) insurance company is loss reserving, which calculates how much money the company should retain in order to pay out future claims. Most P&C insurance companies use non-stochastic (non-random) methods to estimate these future liabilities. However, future loss data can also be projected using generalized linear models (GLMs) and stochastic simulation. Two simulation methods that will be the focus of this project are: bootstrapping methodology, which resamples the original loss data (creating pseudo-data in the process) and fits the GLM parameters based on the new data to estimate the sampling …

Mathematical Modeling Of Trending Topics On Twitter, Jonathan S. Skaza

Honors Projects in Mathematics

Created in 2006, Twitter is an online social networking service in which users share and read 140-character messages called Tweets. The site has approximately 288 million monthly active users who produce about 500 million Tweets per day. This study applies dynamical and statistical modeling strategies to quantify the spread of information on Twitter. Parameter estimates for the rates of infection and recovery are obtained using Bayesian Markov Chain Monte Carlo (MCMC) methods. The methodological strategy employed is an extension of techniques traditionally used in an epidemiological and biomedical context (particularly in the spread of infectious disease). This study, which addresses …

Precipitation Forecasting With Gamma Distribution Models For Gridded Precipitation Events In Eastern Oklahoma And Northwestern Arkansas, Andrew Lang, Steven A. Amburn, Michael A. Buonaiuto

College of Science and Engineering Faculty Research and Scholarship

An elegant and easy to implement probabilistic quantitative precipitation forecasting model that can be used to estimate the probability of exceedance (POE) is presented. The model was built using precipitation data collected across eastern Oklahoma and northwestern Arkansas from late 2005 through early 2013. The dataset includes precipitation analyses at 4578 contiguous, 4 km34 kmgrid cells for 1800 precipitation events of 12 h. The dataset is unique in that the meteorological conditions for each 12-h event were relatively homogeneous when contrasted with single-point data obtained over months or years where the meteorological conditions for each rain event could have varied …

Sensitivity Of Mixed Models To Computational Algorithms Of Time Series Data, Gunaime Nevine

Doctoral Dissertations

Statistical analysis is influenced by implementation of the algorithms used to execute the computations associated with various statistical techniques. Over many years; very important criteria for model comparison has been studied and examined, and two algorithms on a single dataset have been performed numerous times. The goal of this research is not comparing two or more models on one dataset, but comparing models with numerical algorithms that have been used to solve them on the same dataset.

In this research, different models have been broadly applied in modeling and their contrasting which are affected by the numerical algorithms in different …

Spatial Analysis Of Passenger Vehicle Use And Ownership And Its Impact On The Sustainability Of Highway Infrastructure Funding, Matthew Volovski

Open Access Dissertations

Across the United States, the sustainability of highway funding is at risk due to increasing need and uncertainty in the factors that drive revenue. Past studies on highway funding sustainability have identified that the root cause of changing highway revenue are the shifts in social demographics and economic characteristics. Unfortunately, from the revenue perspective (the focus of this dissertation), the ability of previous research to account for these factors has been rather limited in two ways; first, the inability to accurately assess current regional vehicle use (a typical prerequisite for statistical modeling of highway revenues) due to difficulties associated with …

The Stability Of The Iris As A Biometric Modality, Benjamin Wright Petry

Open Access Theses

In this thesis, the question of the stability of a group of individual subjects' irises is examined and answered. This stability is examined in regards to the time scale of the month range. The covariate for this research was time. Images collected during one month of separation between captures were examined. The genuine and impostor scores for these images were calculated and then interpreted using the stability score index. This index produced a quantifiable value for the stability of iris match scores over the months of the examination. ^ Additionally, a new framework for collecting and analyzing time in biometrics …

A Pure-Jump Market-Making Model For High-Frequency Trading, Chi Wai Law

Open Access Dissertations

We propose a new market-making model which incorporates a number of realistic features relevant for high-frequency trading. In particular, we model the dependency structure of prices and order arrivals with novel self- and cross-exciting point processes. Furthermore, instead of assuming the bid and ask prices can be adjusted continuously by the market maker, we formulate the market maker's decisions as an optimal switching problem. Moreover, the risk of overtrading has been taken into consideration by allowing each order to have different size, and the market maker can make use of market orders, which are treated as impulse control, to get …