Open Access. Powered by Scholars. Published by Universities.®

Statistics and Probability Commons

Open Access. Powered by Scholars. Published by Universities.®

10648 Full-Text Articles 13972 Authors 1580531 Downloads 165 Institutions

All Articles in Statistics and Probability

Faceted Search

10648 full-text articles. Page 1 of 295.

Penalized Nonparametric Scalar-On-Function Regression Via Principal Coordinates, Philip T. Reiss, David L. Miller, Pei-Shien Wu, Wen-Yu Hua 2016 New York University School of Medicine

Penalized Nonparametric Scalar-On-Function Regression Via Principal Coordinates, Philip T. Reiss, David L. Miller, Pei-Shien Wu, Wen-Yu Hua

Philip T. Reiss

A number of classical approaches to nonparametric regression have recently been extended to the case of functional predictors. This paper introduces a new method of this type, which extends intermediate-rank penalized smoothing to scalar-on-function regression. The core idea is to regress the response on leading principal coordinates defined by a relevant distance among the functional predictors, while applying a ridge penalty. Our publicly available implementation, based on generalized additive modeling software, allows for fast optimal tuning parameter selection and for extensions to multiple functional predictors, exponential family-valued responses, and mixed-effects models. In an application to signature verification data, the proposed ...


What Will Happen Here?, Sidney Fourteen 2016 bepress university

What Will Happen Here?, Sidney Fourteen

Sidney Fourteen

Ut nisl justo, suscipit et sem vel, consequat euismod leo. Fusce in ultrices dui, at suscipit odio. Pellentesque consequat, diam maximus convallis molestie, est ipsum sagittis sem, sit amet vestibulum tortor ligula in lectus. Sed congue ipsum nulla, nec pharetra diam aliquet non. Aenean interdum augue diam, ac tristique elit blandit non. Etiam rhoncus in sapien sed suscipit. Quisque ac est eu justo sodales ornare. Duis tempor congue orci vitae ornare. Proin eu tellus lacus. Proin luctus ante at iaculis feugiat. In eget erat ac lacus iaculis interdum eget vel massa.


A Multi-Indexed Logistic Model For Time Series, Xiang Liu 2016 East Tennessee State University

A Multi-Indexed Logistic Model For Time Series, Xiang Liu

Electronic Theses and Dissertations

In this thesis, we explore a multi-indexed logistic regression (MILR) model, with particular emphasis given to its application to time series. MILR includes simple logistic regression (SLR) as a special case, and the hope is that it will in some instances also produce significantly better results. To motivate the development of MILR, we consider its application to the analysis of both simulated sine wave data and stock data. We looked at well-studied SLR and its application in the analysis of time series data. Using a more sophisticated representation of sequential data, we then detail the implementation of MILR. We compare ...


Probabilistic Methods In Information Theory, Erik W. Pachas 2016 Cal State University-San Bernardino

Probabilistic Methods In Information Theory, Erik W. Pachas

Electronic Theses, Projects, and Dissertations

Given a probability space, we analyze the uncertainty, that is, the amount of information of a finite system, by studying the entropy of the system. We also extend the concept of entropy to a dynamical system by introducing a measure preserving transformation on a probability space. After showing some theorems and applications of entropy theory, we study the concept of ergodicity, which helps us to further analyze the information of the system.


Hermetic On-Farm Storage For Maize Weevil Control In East Africa, Ali Yakubu, Carl J. Bern, Joel R. Coats, Theodore B. Bailey 2016 Iowa State University

Hermetic On-Farm Storage For Maize Weevil Control In East Africa, Ali Yakubu, Carl J. Bern, Joel R. Coats, Theodore B. Bailey

Carl J. Bern

Maize (Zea mays L.) consumption makes up over half of daily caloric intake of persons in East Africa and adequate supply is necessary for food security for subsistence farmers, as well as for domestic stability. Hermetic post-harvest maize storage is an attractive non-chemical control strategy for maize weevil,Sitophilus zeamais (Motsch.), which is the principal cause of insect damage to stored maize grain. Laboratory experiments were conducted on instrumented hermetic and non-hermetic containers to measure effects of temperature (10 vs. 27°C) and maize moistures (6.3 to 16%) on maize weevil biology and mortality rate, and to quantify weevil ...


Examining Agricultural Investment , Chad Edward Hart 2016 Iowa State University

Examining Agricultural Investment , Chad Edward Hart

Chad Hart

Using two different approaches, the relationship between a firm's investment and its financial variables is examined. Imperfections in the credit market such as asymmetric information have led researchers to explore these relationships. This study incorporates the 5 Cs of lending (character, capacity, collateral, credit rating, and capital) into the farmer's investment decision and explores the impacts of these variables on a basic data set. The data set is composed of 590 Iowa farms that are members of the Iowa Farm Business Association and have reported farm level financial and production data from 1991 to 1995;The first approach ...


Matching The Efficiency Gains Of The Logistic Regression Estimator While Avoiding Its Interpretability Problems, In Randomized Trials With Binary Outcomes, Michael Rosenblum, Jon Arni Steingrimsson 2016 Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics

Matching The Efficiency Gains Of The Logistic Regression Estimator While Avoiding Its Interpretability Problems, In Randomized Trials With Binary Outcomes, Michael Rosenblum, Jon Arni Steingrimsson

Johns Hopkins University, Dept. of Biostatistics Working Papers

Adjusting for prognostic baseline covariates can improve precision in analyzing randomized trials, leading to greater power to detect a treatment effect. For binary outcomes, a logistic regression estimator is commonly used for such adjustment. This has led to substantial efficiency gains in practice; for example, gains equivalent to reducing the required sample size by 20-28% were observed in a recent survey of traumatic brain injury trials. Robinson and Jewell (1991) proved that the logistic regression estimator is guaranteed to have equal or better asymptotic efficiency compared to the unadjusted estimator (which ignores baseline variables). Unfortunately, the logistic regression estimator has ...


Improving Precision By Adjusting For Baseline Variables In Randomized Trials With Binary Outcomes, Without Regression Model Assumptions, Jon Arni Steingrimsson, Daniel F. Hanley, Michael Rosenblum 2016 Johns Hopkins Bloomberg School of Public Health

Improving Precision By Adjusting For Baseline Variables In Randomized Trials With Binary Outcomes, Without Regression Model Assumptions, Jon Arni Steingrimsson, Daniel F. Hanley, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

In randomized clinical trials with baseline variables that are prognostic for the primary outcome, there is potential to improve precision and reduce sample size by appropriately adjusting for these variables. A major challenge is that there are multiple statistical methods to adjust for baseline variables, but little guidance on which is best to use in a given context. The choice of method can have important consequences. For example, one commonly used method leads to uninterpretable estimates if there is any treatment effect heterogeneity, which would jeopardize the validity of trial conclusions. We give practical guidance on how to avoid this ...


After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick 2016 University of Pennsylvania Law School

After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick

Jill Fisch

Event studies have become increasingly important in securities fraud litigation after the Supreme Court’s decision in Halliburton II. Litigants have used event study methodology, which empirically analyzes the relationship between the disclosure of corporate information and the issuer’s stock price, to provide evidence in the evaluation of key elements of federal securities fraud, including materiality, reliance, causation, and damages. As the use of event studies grows and they increasingly serve a gatekeeping function in determining whether litigation will proceed beyond a preliminary stage, it will be critical for courts to use them correctly.

This Article explores an array ...


After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick 2016 University of Pennsylvania Law School

After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick

Jill Fisch

Event studies have become increasingly important in securities fraud litigation after the Supreme Court’s decision in Halliburton II. Litigants have used event study methodology, which empirically analyzes the relationship between the disclosure of corporate information and the issuer’s stock price, to provide evidence in the evaluation of key elements of federal securities fraud, including materiality, reliance, causation, and damages. As the use of event studies grows and they increasingly serve a gatekeeping function in determining whether litigation will proceed beyond a preliminary stage, it will be critical for courts to use them correctly.

This Article explores an array ...


An Exploration Of Information Exchange By Adolescents And Parents Participating In Adolescent Idiopathic Scoliosis Online Support Groups, Traci Schwieger, Shelly Campo, Keli R. Steuber, Stuart L. Weinstein, Sato Ashida 2016 University of Iowa

An Exploration Of Information Exchange By Adolescents And Parents Participating In Adolescent Idiopathic Scoliosis Online Support Groups, Traci Schwieger, Shelly Campo, Keli R. Steuber, Stuart L. Weinstein, Sato Ashida

Department of Biostatistics Publications

Background

Research indicates that healthcare providers frequently fail to adequately address patients’ health information needs. Therefore, it is not surprising that patients or parents of a sick child are seeking health information on the internet, in particular in online support groups (OSGs). In order to improve our understanding of the unmet health information needs of families dealing with adolescent idiopathic scoliosis (AIS), this study assessed and compared the types of information that adolescents and parents are seeking in OSGs.

Methods

This study used two publicly accessible AIS-related OSGs on the National Scoliosis Foundation (NSF) website that targeted those who are ...


Using Machine Learning And Natural Language Processing Algorithms To Automate The Evaluation Of Clinical Decision Support In Electronic Medical Record Systems, Donald A. Szlosek, Jonathan M. Ferretti 2016 University of Southern Maine

Using Machine Learning And Natural Language Processing Algorithms To Automate The Evaluation Of Clinical Decision Support In Electronic Medical Record Systems, Donald A. Szlosek, Jonathan M. Ferretti

eGEMs (Generating Evidence & Methods to improve patient outcomes)

Introduction: As the number of clinical decision support systems incorporated into electronic medical records increases, so does the need to evaluate their effectiveness. The use of medical record review and similar manual methods for evaluating decision rules is laborious and inefficient. Here we use machine learning and natural language processing (NLP) algorithms to accurately evaluate a clinical decision support rule through an electronic medical record system and compare it against manual evaluation.

Methods: Modeled after the electronic medical record system EPIC at Maine Medical Center, we developed a dummy dataset containing physician notes in free text for 3621 artificial patients ...


Statistical Methods For Detecting Groups Of Patterns In Daily Step Count Activity Profiles, Elijah S. Meyer, Tan Tran, Mark Greenwood 2016 Montana State University-Bozeman

Statistical Methods For Detecting Groups Of Patterns In Daily Step Count Activity Profiles, Elijah S. Meyer, Tan Tran, Mark Greenwood

Skyline - The Big Sky Undergraduate Journal

In recent years, “step counting” has become a constant pre-occupation for some people as a way of trying to tie activity to fitness goals. This has been spurred on by inexpensive digital devices that provide a suite of information on how and how much you move during the day. Many of the consumer interfaces to these data provide summary information that often focuses on daily totals and visual displays of patterns of activity if the user dives a little deeper. This suggests that when you move throughout the day is just as much of a story as how much you ...


Projects In Geospatial Data Analysis: Spring 2016, Robert Crimi, Elanor Hoak, Ishita Srivastava, Jesse Wisniewski, Jonathan Blackstock, Keerthi Chikalbettu Pai, Melissa Bica, Michelle Bray, Mikhail Chowdhury, Monal Narasimhamurthy, Nika Shafranov, Sachin Muralidhara, Satchel Spencer, Saurabh Sood, Caleb Phillips 2016 University of Colorado, Boulder

Projects In Geospatial Data Analysis: Spring 2016, Robert Crimi, Elanor Hoak, Ishita Srivastava, Jesse Wisniewski, Jonathan Blackstock, Keerthi Chikalbettu Pai, Melissa Bica, Michelle Bray, Mikhail Chowdhury, Monal Narasimhamurthy, Nika Shafranov, Sachin Muralidhara, Satchel Spencer, Saurabh Sood, Caleb Phillips

Computer Science Technical Reports

This document contains semester projects for students in CSCI 4380/7000 Geospatial Data Analysis (GSA). The course explores the technical aspects of programmatic geospatial data analysis with a focus on GIS concepts, custom GIS programming, analytical and statistical methods, and open source tools and frameworks.


Level Of Patient-Physician Agreement In Assessment Of Change Following Conservative Rehabilitation For Shoulder Pain, Stephanie D. Moore-Reed, W. Ben Kibler, Heather M. Bush, Timothy L. Uhl 2016 California State University, Fresno

Level Of Patient-Physician Agreement In Assessment Of Change Following Conservative Rehabilitation For Shoulder Pain, Stephanie D. Moore-Reed, W. Ben Kibler, Heather M. Bush, Timothy L. Uhl

Tim L. Uhl

Background Assessment of health-related status has been shown to vary between patients and physicians, although the degree of patient–physician discordance in the assessment of the change in status is unknown.

Methods Ninety-nine patients with shoulder dysfunction underwent a standardized physician examination and completed several self-reported questionnaires. All patients were prescribed the same physical therapy intervention. Six weeks later, the patients returned to the physician, when self-report questionnaires were re-assessed and the Global Rating of Change (GROC) was completed by the patient. The physician completed the GROC retrospectively. To determine agreement between patient and physician, intra-class correlation (ICC) coefficient and ...


Multilevel Models For Longitudinal Data, Aastha Khatiwada 2016 East Tennessee State University

Multilevel Models For Longitudinal Data, Aastha Khatiwada

Electronic Theses and Dissertations

Longitudinal data arise when individuals are measured several times during an ob- servation period and thus the data for each individual are not independent. There are several ways of analyzing longitudinal data when different treatments are com- pared. Multilevel models are used to analyze data that are clustered in some way. In this work, multilevel models are used to analyze longitudinal data from a case study. Results from other more commonly used methods are compared to multilevel models. Also, comparison in output between two software, SAS and R, is done. Finally a method consisting of fitting individual models for each ...


After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick 2016 University of Pennsylvania Law School

After Halliburton: Event Studies And Their Role In Federal Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach, Jonathan Klick

Faculty Scholarship

Event studies have become increasingly important in securities fraud litigation after the Supreme Court’s decision in Halliburton II. Litigants have used event study methodology, which empirically analyzes the relationship between the disclosure of corporate information and the issuer’s stock price, to provide evidence in the evaluation of key elements of federal securities fraud, including materiality, reliance, causation, and damages. As the use of event studies grows and they increasingly serve a gatekeeping function in determining whether litigation will proceed beyond a preliminary stage, it will be critical for courts to use them correctly.

This Article explores an array ...


Newsvendor Models With Monte Carlo Sampling, Ijeoma W. Ekwegh 2016 East Tennessee State University

Newsvendor Models With Monte Carlo Sampling, Ijeoma W. Ekwegh

Electronic Theses and Dissertations

Newsvendor Models with Monte Carlo Sampling by Ijeoma Winifred Ekwegh The newsvendor model is used in solving inventory problems in which demand is random. In this thesis, we will focus on a method of using Monte Carlo sampling to estimate the order quantity that will either maximizes revenue or minimizes cost given that demand is uncertain. Given data, the Monte Carlo approach will be used in sampling data over scenarios and also estimating the probability density function. A bootstrapping process yields an empirical distribution for the order quantity that will maximize the expected profit. Finally, this method will be used ...


Spatio-Temporal Analysis Of Point Patterns, Abdul-Nasah Soale 2016 East Tennessee State University

Spatio-Temporal Analysis Of Point Patterns, Abdul-Nasah Soale

Electronic Theses and Dissertations

In this thesis, the basic tools of spatial statistics and time series analysis are applied to the case study of the earthquakes in a certain geographical region and time frame. Then some of the existing methods for joint analysis of time and space are described and applied. Finally, additional research questions about the spatial-temporal distribution of the earthquakes are posed and explored using statistical plots and models. The focus in the last section is in the relationship between number of events per year and maximum magnitude and its effect on how clustered the spatial distribution is and the relationship between ...


Utilizing Computed Tomography Image Features To Advance Prediction Of Radiation Pneumonitis, Shane P. Krafft 2016 The University of Texas Graduate School of Biomedical Sciences at Houston

Utilizing Computed Tomography Image Features To Advance Prediction Of Radiation Pneumonitis, Shane P. Krafft

UT GSBS Dissertations and Theses (Open Access)

Improving outcomes for non-small-cell lung cancer patients treated with radiation therapy (RT) requires optimizing the balance between local tumor control and risk of normal tissue toxicity. In approximately 20% of patients, severe acute symptomatic lung toxicity, termed radiation pneumonitis (RP), still occurs. Identifying the individuals at risk of RP prior to or early during treatment offers tremendous potential to improve RT by providing the physician with information to assist in making clinical decisions that enhance therapy. Our central goal for this work was to demonstrate the potential gain in predictive accuracy of normal tissue complication probability models for RP by ...


Digital Commons powered by bepress