Statistics and Probability Commons^™

Strengthening Interactions Between Statisticians And Collaborators: Objectives And Sample Sizes, Emily Van Meter, Richard Charnigo

Biostatistics Faculty Publications

No abstract provided.

Quantifying The Statistical Impact Of Grappa In Fcmri Data With A Real-Valued Isomorphism, Iain P. Bruce, Daniel B. Rowe

Mathematics, Statistics and Computer Science Faculty Research and Publications

The interpolation of missing spatial frequencies through the generalized auto-calibrating partially parallel acquisitions (GRAPPA) parallel magnetic resonance imaging (MRI) model implies a correlation is induced between the acquired and reconstructed frequency measurements. As the parallel image reconstruction algorithms in many medical MRI scanners are based on the GRAPPA model, this study aims to quantify the statistical implications that the GRAPPA model has in functional connectivity studies. The linear mathematical framework derived in the work of Rowe , 2007, is adapted to represent the complex-valued GRAPPA image reconstruction operation in terms of a real-valued isomorphism, and a statistical analysis is performed …

U.S. Employment Outlook For 2014: Can The U.S. Economy Stand On Its Own?, Randall W. Eberts

Periodical Articles

No abstract provided.

Reliability-Based Progressive Collapse And Redundancy Analysis Of Bridge Systems, Feng Miao

Dissertations, Theses, and Capstone Projects

Highway bridges like most structural systems are usually designed on a member by member basis and little consideration is provided to the effect of a local failure on system safety. There are concerns that some systems optimized to meet code-specified member design criteria may not provide sufficient levels of structural redundancy to withstand a possible local failure. In fact, a local failure of one structural element may result in the failure of another element creating a chain reaction that might progress throughout the whole structure or a major portion of it leading to a catastrophic collapse. Several recent catastrophic structural …

Measuring The Transmission Matrix For Microwave Radiation Propagating Through Random Waveguides: Fundamentals And Applications, Zhou Shi

Dissertations, Theses, and Capstone Projects

This thesis describes the measurement and analysis of the transmission matrix (TM) for microwave radiation propagating through multichannel random waveguides in the crossover to Anderson localization. Eigenvalues of the transmission matrix and the associated eigenchannels are obtained via a singular value decomposition of the TM. The sum of the transmission eigenvalues yields the transmittance T, which is the classical analog of the dimensionless conductance g. The dimensionless conductance g is the electronic conductance in units of the quantum conductance, G/(e^2/h).

For diffusive waves g>1, approximately g transmission eigenchannels contribute appreciably to the transmittance T. In …

Adaptive Pair-Matching In The Search Trial And Estimation Of The Intervention Effect, Laura Balzer, Maya L. Petersen, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially increase study power. In a common design, candidate units are identified, and their baseline characteristics used to create the best n/2 matched pairs. Within the resulting pairs, the intervention is randomized, and the outcomes measured at the end of follow-up. We consider this design to be adaptive, because the construction of the matched pairs depends on the baseline covariates of all candidate units. As consequence, the observed data cannot be considered as n/2 independent, identically distributed (i.i.d.) pairs of units, as current practice assumes. …

Concomitant Socioeconomic, Behavioral, And Biological Factors Associated With The Disproportionate Hiv Infection Burden Among Black Men Who Have Sex With Men In 6 U.S. Cities, Kenneth H. Mayer, Lei Wang, Beryl A. Koblin, Sharon B. Mannheimer, Manya Magnus, +13 Additional Authors

Epidemiology Faculty Publications

Background

American Black men who have sex with men (MSM) are disproportionately affected by HIV, but the factors associated with this concentrated epidemic are not fully understood.

Methods

Black MSM were enrolled in 6 US cities to evaluate a multi-component prevention intervention, with the current analysis focusing on the correlates of being newly diagnosed with HIV compared to being HIV-uninfected or previously diagnosed with HIV.

Results

HPTN 061 enrolled 1553 Black MSM whose median age was 40; 30% self-identified exclusively as gay or homosexual, 29% exclusively as bisexual, and 3% as transgender. About 1/6th(16.2%) were previously diagnosed with HIV (PD); …

Sample Survey Of Utah Educators, Ben Saville, Dr. Lara Wolfson

Journal of Undergraduate Research

In assessing the performance of schools in Utah (or any other state), a critical component of valid assessment of school performance is hard data. In areas such as student performance, that information is readily available from test scores; but in understanding the job burden of teachers in the Utah educational system, very little hard data is available. I proposed to design a sample survey to address issues in which the state of Utah is “data deficient”, impairing the state’s ability to make well-informed decisions about improving working conditions for teachers. Some issues to be addressed include: the amount of money …

A Statistical Analysis Of Rater Consensus In The Byu Premedical Committee, Alane Izu, Dr. David G. Whiting

Journal of Undergraduate Research

The premedical committee at Brigham Young University exists to assist students in successfully applying to medical school. The committee consists of professors from various departments across campus as well as senior premedical students. Two different committee members interview each eligible student in March and April of the year before the student plans to enter medical school. The interviewers rate the student on a continuous scale from one to five in nine different areas: academic performance, MCAT scores, letters of recommendation, written and personal presentation, personal characteristics, reasons for choosing a medical career, extracurricular activities, involvement in community service, and demonstration …

Adaptive Randomized Trial Designs That Cannot Be Dominated By Any Standard Design At The Same Total Sample Size, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

Prior work has shown that certain types of adaptive designs can always be dominated by a suitably chosen, standard, group sequential design. This applies to adaptive designs with rules for modifying the total sample size. A natural question is whether analogous results hold for other types of adaptive designs. We focus on adaptive enrichment designs, which involve preplanned rules for modifying enrollment criteria based on accrued data in a randomized trial. Such designs often involve multiple hypotheses, e.g., one for the total population and one for a predefined subpopulation, such as those with high disease severity at baseline. We fix …

Significance Of Introduced Bias In The Utah Colleges Exit Poll, Sherstin Merx, Dr. Scott Grimshaw

Journal of Undergraduate Research

Since 1982, Brigham Young University Departments of Statistics and Political Science have sponsored the Utah Colleges Exit Poll (UCEP) as both a research tool and as an experience in applied statistics. However, in designing the poll, UCEP routinely deals with administrative and geographic issues that make the task more difficult. For example, just collecting the necessary information from all 29 Utah counties requires the full attention of a designated “Public Relations” committee. Geography is another problem for UCEP. Certain counties are so remote that it is difficult and expensive to include them in the sample.

Destructive Testing Versus Nondestructive Evaluation: A Statistical Comparison, Geraldine Hansen, Dr. C. Shane Reese

Journal of Undergraduate Research

Researchers and developers in manufacturing and industry are often confronted with the problem of testing component functionality. Two important testing methods used on equipment are destructive testing (DT) or nondestructive evaluation (NDE). DT implies that the part is destroyed by disassembly, or it is destroyed by utilizing the equipment to determine if the part was defective. In the case we examined, DT is like exploding a weapon. DT is very expensive and reduces valuable assets, but it is consistently very accurate. This type of testing is often referred to as obtaining a “snapshot in time” because we know at that …

A Joint Model For Multistate Disease Processes And Random Informative Observation Times, With Applications To Electronic Medical Records Data, Jane M. Lange, Rebecca A. Hubbard, Lurdes Y. T. Inoue, Vladimir Minin

UW Biostatistics Working Paper Series

Multistate models are used to characterize individuals' natural histories through diseases with discrete states. Observational data resources based on electronic medical records pose new opportunities for studying such diseases. However, these data consist of observations of the process at discrete sampling times, which may either be pre-scheduled and non-informative, or symptom-driven and informative about an individual's underlying disease status. We have developed a novel joint observation and disease transition model for this setting. The disease process is modeled according to a latent continuous time Markov chain; and the observation process, according to a Markov-modulated Poisson process with observation rates that …

Statistical Inference For Everyone (Sie), Brian S. Blais

Science and Technology Department Faculty Book Publications

In the field of statistical inference, there are two primary schools of thought. Each has its proponents, but it is generally accepted that on all problems covered in an introductory course, that both approaches are valid and lead to the same numerical values when applied to actual problems. Only one of these approaches is covered in a traditional course, which denies the students access to an entire field of statistical inference. The traditional approach, also called the frequentist or orthodox perspective, leads almost directly to problem above. The other approach, also called Probability Theory as Logic, derives all statistical inference …

Statistical Process Control Methods For Multiple Stream Processes: A Comparative Study, Jared Caleb Christensen, Dr. Scott D. Grimshaw

Journal of Undergraduate Research

The Shewhart control chart is the most common statistical process control (SPC) tool used to determine stability. One fundamental assumption of the Shewhart chart is that the output comes from a single, continuous stream. This implies the monitoring of a single source of variation. Filling machines at many beverage plants violate this assumption because there are central filling units with multiple heads filling individual bottles. The variability of the central filling units is the “natural, continuous variability” of the process in terms of a Shewhart chart. The heads add another source of variability. A different methodology needs to be implemented …

Predictors And Moderators Of Outcomes Of Hiv/Std Sex Risk Reduction Interventions In Substance Abuse Treatment Programs: A Pooled Analysis Of Two Randomized Controlled Trials, Paul Crits-Christoph, Robert Gallop, Jaclyn S. Sadicario, Hannah M. Markell, Donald A. Calsyn, Wan Tang, Hua He, Xin Tu, George Woody

Mathematics Faculty Publications

No abstract provided.

Change Point Testing In Logistic Regression Models With Interaction Term, Youyi Fong, Chongzhi Di, Sallie Permar

UW Biostatistics Working Paper Series

The threshold effect takes place in situations where the relationship between an outcome variable and a predictor variable changes as the predictor value crosses a certain threshold/change point. Threshold effects are often plausible in a complex biological system, especially in defining immune responses that are protective against infections such as HIV-1, which motivates the current work. We study two hypothesis testing problems in change point models. We first compare three different approaches to obtaining a p-value for the maximum of scores test in a logistic regression model with change point variable as a main effect. Next, we study the testing …

Calculating Ellipse Overlap Areas, Gary B. Hughes, Mohcine Chraibi

Statistics

We present an approach for finding the overlap area between two ellipses that does not rely on proxy curves. The Gauss-Green formula is used to determine a segment area between two points on an ellipse. Overlap between two ellipses is calculated by combining the areas of appropriate segments and polygons in each ellipse. For four of the ten possible orientations of two ellipses, the method requires numerical determination of transverse intersection points. Approximate intersection points can be determined by solving the two implicit ellipse equations simultaneously. Alternative approaches for finding transverse intersection points are available using tools from algebraic geometry, …

Student Fact Book, Fall 2014 - Thirty-Eighth Annual Edition, Wright State University, Office Of Student Information Systems, Wright State University

Wright State University Student Fact Books

The student fact book has general demographic information on all students enrolled at Wright State University for Fall Semester, 2014.

On The Joys Of Missing Data, Todd D. Little, Terrence D. Jorgensen, Kyle M. Lang, E. Whitney G. Moore

Kinesiology, Health and Sport Studies

We provide conceptual introductions to missingness mechanisms—missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR)—and state-of-the-art methods of handling missing data—full-information maximum likelihood (FIML) and multiple imputation (MI)—followed by a discussion of planned missing designs: multiform questionnaire protocols, two-method measurement models, and wave-missing longitudinal designs. We reviewed 80 articles of empirical studies published in the 2012 issues of the Journal of Pediatric Psychology to present a picture of how adequately missing data are currently handled in this field. To illustrate the benefits of utilizing MI or FIML and incorporating planned missingness into study designs, …

Using Spss To Understand Research And Data Analysis, Daniel Arkkelin

Psychology Curricular Materials

No abstract provided.

Demonstration Databases (Supplemental To Psychology & Health Article), Blair T. Johnson

CHIP Documents

Here is a database (in Stata, R, SAS, SPSS formats) that was used to demonstrate simple slopes analysis in meta-regression in an online supplement to the article, "Panning for the gold in health research: Incorporating studies’ methodological quality in meta-analysis," published in the journal Psychology & Health in 2014. It is an archive (zip) file that also contains the Stata syntax used in the demonstrations.

Meta-Analysis Of Social-Personality Psychological Research, Blair T. Johnson, Alice H. Eagly

CHIP Documents

This publication provides a contemporary treatment of the subject of meta-analysis in relation to social-personality psychology. Meta-analysis literally refers to the statistical pooling of the results of independent studies on a given subject, although in practice it refers as well to other steps of research synthesis, including defining the question under investigation, gathering all available research reports, coding of information about the studies and their effects, and interpretation/dissemination of results. Discussed as well are the hallmarks of high-quality meta-analyses.

Changing Minds To Changing The World: Mapping The Spectrum Of Intent In Data Visualization And Data Arts, Scott Murray

Art + Architecture

No abstract provided.

A Linear Iteration Algorithm For A Second-Order Energy Stable Scheme For A Thin Film Model Without Slope Selection, Wenbin Chen, Cheng Wang, Xiaoming Wang, Steven M. Wise

Mathematics and Statistics Faculty Research & Creative Works

We present a linear iteration algorithm to implement a second-order energy stable numerical scheme for a model of epitaxial thin film growth without slope selection. the PDE, which is a nonlinear, fourth-order parabolic equation, is the L 2 gradient flow of the energy d x. the energy stability is preserved by a careful choice of the second-order temporal approximation for the nonlinear term, as reported in recent work (Shen et al. in SIAM J Numer Anal 50:105-125, 2012). the resulting scheme is highly nonlinear, and its implementation is non-trivial. in this paper, we propose a linear iteration algorithm to solve …

Linking Instrumental Neutron Activation Analysis (Inaa) With Geology In The Ancestral Caddo Region, Robert Z. Selden Jr.

CRHR: Archaeology

This poster illustrates the success of a novel method of INAA that was employed to reveal geochemical signatures in Caddo ceramic vessel sherds that correlate with local surficial geology. The geochemical data from the sherd assemblage were used within an exploration of potential ceramic provenance, which was successful at demarcating sherds from ceramic vessels made from clays in either the Claiborne or Wilcox Groups. Further geochemical segregation was also apparent between the Recklaw Formation in the Claiborne Group, and the Weches Formation in the Wilcox Group. These results point to a high degree of geochemical variability within the East Texas …

Instrumental Neutron Activation Analysis (Inaa) Of Shell-Tempered Ceramics In The Ancestral Caddo Region: Rethinking Methods, Robert Z. Selden Jr., Timothy K. Perttula

CRHR: Archaeology

The geochemical analysis of shell-tempered ceramics in the ancestral Caddo region has been a matter of confusion since the mid-1990s. While Caddo archaeologists have long perceived most or all of the shell-tempered ceramics in East Texas to have originated from two different areas within the Red River basin, the geochemical data and interpretations remain inconsistent with that idea. This poster takes another look at this dataset, and considers an approach that was initially put forth by MURR, and then seemingly abandoned. Using only the geochemical data from shell-tempered sherds, we take a closer look at the contributions of calcium (Ca), …

Toward A Morphometric Phylogeny Of Caddo Ceramics: A Test Of 3d Geometric Morphometrics, Robert Z. Selden Jr., Timothy K. Perttula, Michael J. O'Brien

CRHR: Archaeology

In this poster we use 3D geometric morphometrics as an exploratory tool for examining diversity in vessel form (or shape) among 27 whole or reconstructed Caddo vessels from the Vanderpool site in Smith County, Texas. Forty-one landmarks from each vessel were exported to version 2.5 of Morphologika for generalized Procrustes analysis and principal components analysis and were then exported to R for cluster analysis (depending on sample size). Despite the small sample size, results indicate that 3D geometric morphometric analysis is an avenue of ceramic research where substantive analytical gains can be realized.

Advances In Documentation, Digital Curation, Virtual Exhibition, And A Test Of 3d Geometric Morhpometrics: A Case Study Of The Vanderpool Vessels From The Ancestral Caddo Territory, Robert Z. Selden Jr., Timothy K. Perttula, Michael J. O'Brien

CRHR: Archaeology

Three-dimensional (3D) digital scanning of archaeological materials is typically used as a tool for artifact documentation. With the permission of the Caddo Nation of Oklahoma, 3D documentation of Caddo funerary vessels from the Vanderpool site (41SM77) was conducted with the initial goal of ensuring that these data would be publicly available for future research long after the vessels were repatriated. A digital infrastructure was created to archive and disseminate the resultant 3D datasets, ensuring that they would be accessible by both researchers and the general public (CRHR 2014a). However, 3D imagery can be used for much more than documentation. To …

Extending Mendelian Risk Prediction Models To Handle Misreported Family History, Danielle Braun, Malka Gorfine, Hormuzd A. Katki, Argyrios Ziogas, Hoda Anton-Culver, Giovanni Parmigiani

Harvard University Biostatistics Working Paper Series

Mendelian risk prediction models calculate the probability of a proband being a mutation carrier based on family history and known mutation prevalence and penetrance. Family history in this setting, is self-reported and is often reported with error. Various studies in the literature have evaluated misreporting of family history. Using a validation data set which includes both error-prone self-reported family history and error-free validated family history, we propose a method to adjust for misreporting of family history. We estimate the measurement error process in a validation data set (from University of California at Irvine (UCI)) using nonparametric smoothed Kaplan-Meier estimators, and …