Applied Statistics Commons^™

Estimating The Accuracy Of Automated Classification Systems Using Only Expert Ratings That Are Less Accurate Than The System, Paul E. Lehner

Journal of Modern Applied Statistical Methods

A method is presented to estimate the accuracy of an automated classification system based only on expert ratings on test cases, where the system may be substantially more accurate than the raters. In this method an estimate of overall rater accuracy is derived from the level of inter-rater agreement, Bayesian updating based on estimated rater accuracy is applied to estimate a ground truth probability for each classification on each test case, and then overall system accuracy is estimated by comparing the relative frequency that the system agrees with the most probable classification at different probability levels. A simulation analysis provides …

Modeling Probability Of Causal And Random Impacts, Stan Lipovetsky, Igor Mandel

Journal of Modern Applied Statistical Methods

The method of the estimation of the probability of an event occurring under the influence of the causal and random effects is considered. Epistemological differences from the traditional approaches to causality are discussed, and a new model of the statistical estimation of the parameters of each effect is proposed. The simple and effective algorithms of the model parameters estimation are presented, and numerical simulations are performed. A practical marketing example is analyzed. The results support the validity of the estimation procedure and open the perspective for the application of the method for various decision making problems, where different causes can …

Estimation For The Parameters Of The Exponentiated Exponential Distribution Using A Median Ranked Set Sampling, Monjed H. Samuh, Areen Qtait

Journal of Modern Applied Statistical Methods

The method of maximum likelihood estimation based on Median Ranked Set Sampling (MRSS) was used to estimate the shape and scale parameters of the Exponentiated Exponential Distribution (EED). They were compared with the conventional estimators. The relative efficiency was used for comparison. The amount of information (in Fisher's sense) available from the MRSS about the parameters of the EED were be evaluated. Confidence intervals for the parameters were constructed using MRSS.

A Decision Support Tool For Appointment Scheduling To Reduce Patient No-Show Rate In An Outpatient Psychiatric Clinic, Kaitlyn N. Thomas

Industrial Engineering Undergraduate Honors Theses

The Walker Family Clinic in the Psychiatric Research Institute at the University of Arkansas for Medical Sciences in Little Rock, Arkansas provides general and specialty mental health and substance abuse services for adolescents and adults. As there is an increasing need for health services at the clinic, the current capacity may not be able to meet all demands. Patients may wait a long time before receiving care due to inefficiencies in the current system. Also, based on data collected from August 1, 2013 to November 26, 2014, the average daily no-show rate was 13.9% and the maximum daily no-show rate …

Estimating The Strength Of An Association Based On A Robust Smoother, Rand Wilcox

Journal of Modern Applied Statistical Methods

It is known that the more obvious parametric approaches to fitting a regression line to data are often not flexible enough to provide an adequate approximation of the true regression line. Many nonparametric regression estimators, often called smoothers, have been derived that are aimed at dealing with this problem. The paper deals with the issue of estimating the strength of an association based on the fit obtained by a robust smoother. A simple approach, already known, is to estimate explanatory power in a fairly obvious manner. This approach has been found to perform reasonably well when using the smoother LOESS. …

Per Family Or Familywise Type I Error Control: "Eether, Eyether, Neether, Nyther, Let's Call The Whole Thing Off!", H. J. Keselman

Journal of Modern Applied Statistical Methods

Frane (2015) pointed out the difference between per-family and familywise Type I error control and how different multiple comparison procedures control one method but not necessarily the other. He then went on to demonstrate in the context of a two group multivariate design containing different numbers of dependent variables and correlations between variables how the per-family rate inflates beyond the level of significance. In this article I reintroduce other newer better methods of Type I error control. These newer methods provide more power to detect effects than the per-family and familywise techniques of control yet maintain the overall rate of …

Comparison Of Bayesian Credible Intervals To Frequentist Confidence Intervals, Kathy Gray, Brittany Hampton, Tony Silveti-Falls, Allison Mcconnell, Casey Bausell

Journal of Modern Applied Statistical Methods

Frequentist confidence intervals were compared with Bayesian credible intervals under a variety of scenarios to determine when Bayesian credible intervals outperform frequentist confidence intervals. Results indicated that Bayesian interval estimation frequently produces results with precision greater than or equal to the frequentist method.

Special Education Distributions And Analysis, Valerie Felder, Shlomo S. Sawilowsky

Journal of Modern Applied Statistical Methods

Micceri (1989) examined the distributional characteristics of 440 large sample general education achievement and psychometric measures. All the distributions were found to be statistically significantly different from the normal distribution. In this study, 395 special education datasets were examined. Although there were some normally distributed datasets, most were not, and some were markedly different in shape from those found by Micceri (1989). Implications for statistical testing and making special education policy decisions were given.

Vol. 14, No. 1 (Full Issue), Jmasm Editors

Journal of Modern Applied Statistical Methods

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A Comparison Of Semi-Parametric And Nonparametric Methods For Estimating Mean Time To Event For Randomly Left Censored Data, Farzana Chowdhury, Jahida Gulshan, Syed Shahadat Hossain

Journal of Modern Applied Statistical Methods

The aim of this study was to make a comparison among existing estimation methods (Kaplan-Meier, Nelson-Aalen and Regression on Ordered Statistics (ROS)) for randomly left censored time to event data under selected distributions and for different level of censoring and sample sizes in order to determine the strength of these methods based on simulated data. Comparisons among the methods are made on the basis of unbiasedness and Monte Carlo Standard Error of the summary statistics (mean time to event) obtained by those methods under different conditions.

The Minimal Zn-Symmetric Graphs That Are Not Zn-Spherical, Lowell Abrams, Dan Slilaty

Mathematics and Statistics Faculty Publications

Given a graph G equipped with faithful and fixed-point-free Γ-action (Γ a finite group) we define an orbit minor H of G to be a minor of G for which the deletion and contraction sets are closed under the Γ-action. The orbit minor H inherits a Γ-symmetry from G, and when the contraction set is acyclic the action inherited by H remains faithful and fixed-point free. When G embeds in the sphere and the Γ-action on G extends to a Γ-action on the entire sphere, we say that G is Γ-spherical. In this paper we determine for every odd value …

A Comparison Of Population-Averaged And Cluster-Specific Approaches In The Context Of Unequal Probabilities Of Selection, Natalie A. Koziol

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Sampling designs of large-scale, federally funded studies are typically complex, involving multiple design features (e.g., clustering, unequal probabilities of selection). Researchers must account for these features in order to obtain unbiased point estimators and make valid inferences about population parameters. Single-level (i.e., population-averaged) and multilevel (i.e., cluster-specific) methods provide two alternatives for modeling clustered data. Single-level methods rely on the use of adjusted variance estimators to account for dependency due to clustering, whereas multilevel methods incorporate the dependency into the specification of the model.

Although the literature comparing single-level and multilevel approaches is vast, comparisons have been limited to the …

A New Approach To Modeling Multivariate Time Series On Multiple Temporal Scales, Tucker Zeleny

Department of Statistics: Dissertations, Theses, and Student Research

In certain situations, observations are collected on a multivariate time series at a certain temporal scale. However, there may also exist underlying time series behavior on a larger temporal scale that is of interest. Often times, identifying the behavior of the data over the course of the larger scale is the key objective. Because this large scale trend is not being directly observed, describing the trends of the data on this scale can be more difficult. To further complicate matters, the observed data on the smaller time scale may be unevenly spaced from one larger scale time point to the …

Roulette: More Than Just A Chance, David Abuhanna

Honors College Theses

Data were generated using a physical roulette wheel to test whether an association exists between initial conditions (the pocket from which the ball is released) and output (the pocket where the ball lands). I have generated data to determine whether there exists statistical significance in distributions of adjoined pockets. Using the statistical software Excel for data tabulation and mapping and using R for statistical computations, I determined a possible method for cheating. I also established an association does in fact exist between initial conditions and output. The existence of this association diminishes roulette as a game of "pure" chance. The …

Analytical Comparison Of Contrasting Approaches To Estimating Competing Risks Models, Brian Stephen Rickard

Graduate Theses and Dissertations

Survival analysis is a commonly used tool in many fields but has seen little use in education research despite a common number of research questions for which it is well suited. Researchers often use logistic regression instead; however, this omits useful information. In research on retention and graduation for example, the timing of the event is an important piece of information omitted when using logistic regression. A simulation study was conducted to evaluate four methods of analyzing competing risks survival data, Cox proportional hazards regression, Weibull regression, Fine and Gray's Method, and Cox proportional hazards regression with frailty. College student …

The Effects Of Instruction On Landing Strategies In Female College-Aged Dancers And Non-Dancers: A Pilot Study, Brittany Keating, Jason Pyfer, Kimberly Vialpando

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background Female athletic participation has increased over the past decade and with it the prevalence of knee injuries. Current research demonstrates an increased risk of anterior cruciate ligament (ACL) injury for female athletes. However, a number of studies have pointed out that ballet and modern dancers exhibit a lower incidence of ACL injuries despite the fact that they perform jumping and landing frequently.

Objective The objective of this study was to examine how dance experience and instruction affect the lower extremity biomechanics during drop landings. Specifically, lower extremity joint alignment and muscle activation of gluteus maximus and gluteus medius were …

The Effects Of Enhanced And Decreased Expectations On Balance Performance In Those With And Without Parkinson’S Disease, Joshua Ostrander, Granuaile Parrish, Jacob Blood

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: It has been reported individuals typically perform well on a task when enhanced expectancy was provided prior to task performance. It has also been reported people with Parkinson’s disease (PD) are especially susceptible to pre-task placebo cuing and suggestion. Evidence of this susceptibility has been previously demonstrated through brain imaging studies and with demonstration by individuals with PD improved balance performance.

Objective: This study was designed to further previous studies’ results for improved task performance with enhanced expectancy. The purpose of this study was to investigate if the pre-task verbal delivery of enhanced expectancy, decreased expectancy and no expectancy …

Comparing Usability And Variance Of Low- And High Technology Approaches To Gait Analysis In Health Adults, John Mcconnell, Brian Silverman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: The purpose of this study was to compare the usability, reliability, and objectivity of four tools that represented varying gait analysis technologies used in clinical practice and/or research. Low technology clinical tools included the Gait Abnormality Rating Scale (GARS-M) and the Rancho Los Amigos Observational Gait Analysis (Rancho OGA). High technology tools included the GAITRiteÒ computerized walkway, and the APDM Mobility LabÔ wearable sensor system.

Subjects: 74 healthy adults ages 18-41 years (mean = 24.82, SD = 4.39) 33 males and 40 females.

Methods: Subjects were instructed to walk at a self-selected speed for two minutes …

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 …

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 …

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 …

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.

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 …

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 …

Zero-Inflated Models To Identify Transcription Factor Binding Sites In Chip-Seq Experiments, Sameera Dhananjaya Viswakula

Mathematics & Statistics Theses & Dissertations

It is essential to determine the protein-DNA binding sites to understand many biological processes. A transcription factor is a particular type of protein that binds to DNA and controls gene regulation in living organisms. Chromatin immunoprecipitation followed by highthroughput sequencing (ChIP-seq) is considered the gold standard in locating these binding sites and programs use to identify DNA-transcription factor binding sites are known as peak-callers. ChIP-seq data are known to exhibit considerable background noise and other biases. In this study, we propose a negative binomial model (NB), a zero-inflated Poisson model (ZIP) and a zero-inflated negative binomial model (ZINB) for peak-calling. …

Dialectical Behavior Therapy For High Suicide Risk In Individuals With Borderline Personality Disorder: A Randomized Clinical Trial And Component Analysis, Marsha M. Linehan, Kathryn E. Korslund, Melanie S. Harned, Robert J. Gallop, Anita Lungu, Andrada D. Neacsiu, Joshua Mcdavid, Katherine Anne Comtois, Angela M. Murray-Gregory

Mathematics Faculty Publications

No abstract provided.

Predicting Successful Long-Term Weight Loss From Short-Term Weight-Loss Outcomes: New Insights From A Dynamic Energy Balance Model (The Pounds Lost Study), Diana Thomas, W Andrada Ivanescu, Corby K. Martin, Steven B. Heymsfield, Kaitlyn Marshall, Victoria E. Bodrato, Donald Williamson, Stephen Anton, Frank M. Sacks, Donna Ryan, George A. Bray

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

Background: Currently, early weight-loss predictions of long-term weight-loss success rely on fixed percent-weight-loss thresholds.

Objective: The objective was to develop thresholds during the first 3 mo of intervention that include the influence of age, sex, baseline weight, percent weight loss, and deviations from expected weight to predict whether a participant is likely to lose 5% or more body weight by year 1.

Design: Data consisting of month 1, 2, 3, and 12 treatment weights were obtained from the 2-y Preventing Obesity Using Novel Dietary Strategies (POUNDS Lost) intervention. Logistic regression models that included covariates of age, height, sex, baseline weight, …