Physical Sciences and Mathematics Commons^™

A Bayesian Approach To Deriving Ages Of Individual Field White Dwarfs, Erin M. O'Malley, Ted Von Hippel, David A. Van Dyk

Ted von Hippel

We apply a self-consistent and robust Bayesian statistical approach to determine the ages, distances, and zero-age main sequence (ZAMS) masses of 28 field DA white dwarfs (WDs) with ages of approximately 4-8 Gyr. Our technique requires only quality optical and near-infrared photometry to derive ages with <15% uncertainties, generally with little sensitivity to our choice of modern initial-final mass relation. We find that age, distance, and ZAMS mass are correlated in a manner that is too complex to be captured by traditional error propagation techniques. We further find that the posterior distributions of age are often asymmetric, indicating that the standard approach to deriving WD ages can yield misleading results.

Differentially Expressed Genes In Blood From Young Pigs Between Two Swine Lines Divergently Selected For Feed Efficiency: Potential Biomarkers For Improving Feed Efficiency, Haibo Liu, Yet T. Nguyen, Daniel S. Nettleton, Jack C. M. Dekkers, Christopher K. Tuggle

Dan Nettleton

The goal of this study was to find potential gene expression biomarkers in blood of piglets that can be used to predict pigs’ future feed efficiency. Using RNA-seq technology, we found 453 genes were differentially expressed (false discovery rate (FDR) ≤ 0.05) in the blood of two Yorkshire lines of pigs divergently selected for feed efficiency (FE) based on residual feed intake (RFI). Genes involved in several biosynthetic processes were overrepresented among genes more highly expressed in the low RFI line compared to the high RFI line. Weighted gene co-expression network analysis (WGCNA) also revealed genes involved in some of …

A Self-Contained Course In The Mathematical Theory Of Statistics For Scientists & Engineers With An Emphasis On Predictive Regression Modeling & Financial Applications., Tim Smith

Timothy Smith

Preface & Acknowledgments

This textbook is designed for a higher level undergraduate, perhaps even first year graduate, course for engineering or science students who are interested to gain knowledge of using data analysis to make predictive models. While there is no statistical perquisite knowledge required to read this book, due to the fact that the study is designed for the reader to truly understand the underlying theory rather than just learn how to read computer output, it would be best read with some familiarity of elementary statistics. The book is self-contained and the only true perquisite knowledge is a solid …

The Gaise College Report: The American Statistical Association Meets Sound Pedagogy In Central Virginia, Beverly Wood

Beverly Wood

Research in undergraduate statistics education often centers on the introductory course required for a large percentage of college students. While acknowledging the diverse setting, audience, and purpose of introductory courses, existing research assumes that courses offered by different disciplines share the same goals and teaching practices. The purpose of this study is to examine the objectives for student outcomes and pedagogical delivery of introductory statistics courses in various academic departments to provide explicit evidence for this assumption. The American Statistical Association’s Guidelines for Assessment and Instruction in Statistics Education (GAISE) are meant to apply to all introductory courses. The College …

Guidelines For Assessment And Instruction In Statistics Education (Gaise) College Report 2016, Robert Carver, Michelle Everson, John Gabrosek, Nicholas Horton, Robin Lock, Megan Mocko, Allan Rossman, Ginger Holmes Roswell, Paul Velleman, Jeffrey Witmer, Beverly Wood

Beverly Wood

In 2005 the American Statistical Association (ASA) endorsed the Guidelines for Assessment and Instruction in Statistics Education (GAISE) College Report. This report has had a profound impact on the teaching of introductory statistics in two- and four-year institutions, and the six recommendations put forward in the report have stood the test of time. Much has happened within the statistics education community and beyond in the intervening 10 years, making it critical to re-evaluate and update this important report. For readers who are unfamiliar with the original GAISE College Report or who are new to the statistics education community, the full …

Data Analysis Basics – Part Ii, Judith A. Savageau

Judith A. Savageau

Blog post to AEA365, a blog sponsored by the American Evaluation Association (AEA) dedicated to highlighting Hot Tips, Cool Tricks, Rad Resources, and Lessons Learned for evaluators. The American Evaluation Association is an international professional association of evaluators devoted to the application and exploration of program evaluation, personnel evaluation, technology, and many other forms of evaluation. Evaluation involves assessing the strengths and weaknesses of programs, policies, personnel, products, and organizations to improve their effectiveness.

Data Analysis Basics – Part I, Judith A. Savageau

Judith A. Savageau

Blog post to AEA365, a blog sponsored by the American Evaluation Association (AEA) dedicated to highlighting Hot Tips, Cool Tricks, Rad Resources, and Lessons Learned for evaluators. The American Evaluation Association is an international professional association of evaluators devoted to the application and exploration of program evaluation, personnel evaluation, technology, and many other forms of evaluation. Evaluation involves assessing the strengths and weaknesses of programs, policies, personnel, products, and organizations to improve their effectiveness.

Teaching Statistics To Msw Students: Comparing Credit And Non-Credit Options, Ashley Davis, Rebecca G. Mirick

Rebecca Mirick

Statistical Contributions To Bioinformatics: Design, Modeling, Structure Learning, And Integration, Jeffrey S. Morris, Veera Baladandayuthapani

Jeffrey S. Morris

Corn-Soybean And Alternative Cropping Systems Effects On No 3 -N Leaching Losses In Subsurface Drainage Water, Rameshwar S. Kanwar, Richard M. Cruse, Mohammadreza Ghaffarzadeh, Allah Bakhsh, Douglas Karlen, Theodore B. Bailey

Douglas L Karlen

Alternative cropping systems can improve resource use efficiency, increase corn grain yield, and help in reducing negative impacts on the environment. A 6-yr (1993 to 1998) field study was conducted at the Iowa State University’s Northeastern Research Center near Nashua, Iowa, to evaluate the effects of non-traditional cropping systems [strip inter cropping (STR)-corn (Zea mays L.)/soybean (Glycine max L.)/oats (Avina sativa L.)]; alfalfa rotation (ROT)-3-yr (1993 to 1995) alfalfa (Medicago sativa L.) followed by corn in 1996, soybean in 1997, and oats in 1998), and traditional cropping system (corn after soybean (CS) and soybean after corn (SC) on the flow …

Cropping System Effects On No3-N Loss With Subsurface Drainage Water, Allah Bakhsh, Rameshwar S. Kanwar, Theodore B. Bailey, Cynthia A. Cambardella, Douglas Karlen, Thomas S. Colvin

Douglas L Karlen

An appropriate combination of tillage and nitrogen management practices will be necessary to develop sustainable farming practices. A six–year (1993–1998) field study was conducted on subsurface–drained Clyde–Kenyon–Floyd soils to quantify the impact of two tillage systems (chisel plow vs. no tillage) and two N fertilizer management practices (preplant single application vs. late–spring soil test based application) on nitrate–nitrogen (NO3–N) leaching loss with subsurface drain discharge from corn (Zea mays L.) soybean (Glycine max L.) rotation plots. Preplant injected urea ammonium nitrate solution (UAN) fertilizer was applied at the rate of 110 kg ha–1 to chisel plow and no–till corn plots, …

Measuring Gender Difference In Information Sharing Using Network Analysis: The Case Of The Austrian Interlocking Directorship Network In 2009, Carlo Drago, Livia Amidani Aliberti, Davide Carbonai

Carlo Drago

In recent literature a relevant problem has been the relationship between career/personal contact networks and different career paths. In addition the recent advances in social capital theory have shown the way in which networks impact on personal careers. In particular women’s careers appear to be negatively affected by the informational network structure. The main contribution of this work is to propose empirical evidence of this phenomenon by considering the gendered directorship network with relation to Austria and to show the structural differences by gender in the network. By using community detection techniques we have found various communities in which females …

Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak

Professor Noel Cressie

Techniques for the analysis of spatial data have, to date, tended to ignore any effect caused by error in specifying the spatial locations at which measurements are recorded. This paper reviews the methods for adjusting spatial inference in the presence of data-location error, particularly for data that. have a continuous spatial index (geostatistical data). New kriging equations are developed and evaluated based on a simulation experiment. They are also applied to remote-sensing data from the Total Ozone Mapping Spectrometer instrument on the Nimbus-7 satellite, where the location error is caused by assignment of the data to their nearest grid-cell centers. …

Size And Power Considerations For Testing Loglinear Models Using Divergence Test Statistics, Noel A. Cressie, L Pardo, M Del Carmen Pardo

Professor Noel Cressie

In this article, we assume that categorical data are distributed according to a multinomial distribution whose probabilities follow a loglinear model. The inference problem we consider is that of hypothesis testing in a loglinear-model setting. The null hypothesis is a composite hypothesis nested within the alternative. Test statistics are chosen from the general class of divergence statistics. This article collects together the operating characteristics of the hypothesis test based on both asymptotic (using large-sample theory) and finite-sample (using a designed simulation study) results. Members of the class of power divergence statistics are compared, and it is found that the Cressie-Read …

Data Mining Of Misr Aerosol Product Using Spatial Statistics, Tao Shi, Noel A. Cressie

Professor Noel Cressie

In climate models, aerosol forcing is the major source of uncertainty in climate forcing, over the industrial period. To reduce this uncertainty, instruments on satellites have been put in place to collect global data. However, missing and noisy observations impose considerable difficulties for scientists researching global aerosol distribution, aerosol transportation, and comparisons between satellite observations and global-climate-model outputs. In this paper, we propose a Spatial Mixed Effects (SME) statistical model to predict the missing values, denoise the observed values, and quantify the spatial-prediction uncertainties. The computations associated with the SME model are linear scalable to the number of data points, …

Decomposition Of High Frequency Data In Components: Visualization And Interpretative Models, Carlo Drago

Carlo Drago

No abstract provided.

A Note On The Indeterminacy And Arbitrariness Of Pena’S Method Of Construction Of Synthetic Indicators, Sudhanshu K. Mishra

Sudhanshu K Mishra

In this paper we demonstrate that Pena’s method of construction of a synthetic indicator is very sensitive to the order in which the constituent variables (whose linear aggregation yields the synthetic indicator) are arranged. Since m number of constituent variables may be arranged in m-factorial ways, even a moderately large m can give rise to a very large number of synthetic indicators from which one cannot choose the one which best represents the constituent variables. Given that an analyst has too little information as to the order in which a sizeable number of constituent variables must be arranged so as …

The Dirty “S” Word: Innovative Teaching Techniques For Counselor Educators Facilitating Learning In Statistics And Research, Rebecca L. Tadlock-Marlo, Megan Michalak

Rebecca L Tadlock-Marlo

Innovative pedagogy will be presented and discussed to help make research a less painful class to both teach and learn. Foci include teaching methods, potential assignments, and suggestions for activities to help facilitate a more fluid learning process for counselors. Attendees will explore aspects of helping students overcome their fear of both statistics and research.

A Statistical Test For The Capacity Coefficient, Joseph W. Houpt, James T. Townsend

Joseph W. Houpt

No abstract provided.

Statistics In Law: Bad Inferences & Uncommon Sense, Curtis E.A. Karnow

Curtis E.A. Karnow

A review of classic fallacies in statistics and probability in the courts. The article briefly, and in plain English, provides an introduction to probability theory, and randomness.

National Estimates Of The Prevalence Of Alzheimer's Disease In The United States, Ron Brookmeyer, Denis Evans, Liesi Hebert, Langa Kenneth, Heeringa Steven, Plassman Brenda, Kukull Kenneth

Ron Brookmeyer

Several methods of estimating prevalence of dementia are presented in this article. For both Brookmeyer and the Chicago Health and Aging project (CHAP), the estimates of prevalence are derived statistically, forward calculating from incidence and survival figures. The choice of incidence rates on which to build the estimates may be critical. Brookmeyer used incidence rates from several published studies, whereas the CHAP investigators applied the incidence rates observed in their own cohort. The Aging, Demographics, and Memory Study (ADAMS) and the East Boston Senior Health Project (EBSHP) were sample surveys designed to ascertain the prevalence of Alzheimer’s disease and dementia. …

Big Macs And Eigenfactor Scores: Don't Let The Correlation Coefficients Fool You, Jevin D. West, Carl T. Bergstrom, Theodore C. Bergstrom

Ted C Bergstrom

A recent article by Phil Davis suggested that the Eigenvalue metric does adds little useful information to the more simply calculated measure of total citations published by the ISI. This paper argues that Davis's claim is an instance of a classic statistical fallacy of spurious correlation. Based on an analysis of the entire 2006 ISI Journal Citation Reports, we show that there are statistically and economically significant differences between the Eigenfactor metrics and the ISI's impact factor and total citations.

Temporal Changes In The Parameters Of Statistical Distribution Of Journal Impact Factor, Sudhanshu K. Mishra

Sudhanshu K Mishra

Statistical distribution of Journal Impact Factor (JIF) is characteristically asymmetric and non-mesokurtic. Even the distribution of log10(JIF) exhibits conspicuous skewness and non-mesokurticity. In this paper we estimate the parameters of Johnson SU distribution fitting to the log10(JIF) data for 10 years, 1999 through 2008, and study the temporal variations in those estimated parameters. We also study ‘over-the-samples stability’ in the estimated parameters for each year by the method of re-sampling close to bootstrapping. It has been found that log10(JIF) is Pearson-IV distributed. Johnson SU distribution fits very well to the data and yields parameters stable over the samples. We conclude …

Empirical Probability Distribution Of Journal Impact Factor And Over-The-Samples Stability In Its Estimated Parameters, Sudhanshu K. Mishra

Sudhanshu K Mishra

The data on JIFs provided by Thomson Scientific can only be considered as a sample since they do not cover the entire universe of those documents that cite an intellectual output (paper, article, etc) or are cited by others. Then, questions arise if the empirical distribution (best fit to the JIF data for any particular year) really represents the true or universal distribution, are its estimated parameters stable over the samples and do they have some scientific interpretation? It may be noted that if the estimated parameters do not exhibit stability over the samples (while the sample size is large …

A Note On Empirical Sample Distribution Of Journal Impact Factors In Major Discipline Groups, Sudhanshu K. Mishra

Sudhanshu K Mishra

What type of statistical distribution do the Journal Impact Factors follow? In the past, researchers have hypothesized various types of statistical distributions underlying the generation mechanism of journal impact factors. These are: lognormal, normal, approximately normal, Weibull, negative exponential, combination of exponentials, Poisson, Generalized inverse Gaussian-Poisson, negative binomial, generalized Waring, gamma, etc. It is pertinent to note that the major characteristics of JIF data lay in the asymmetry and non-mesokurticity. The present study, frequently encounters Burr-XII, inverse Burr-III (Dagum), Johnson SU, and a few other distributions closely related to Burr distributions to best fit the JIF data in subject groups …

On The Statistical Accuracy Of Biomarker Assays Of Hiv Incidence, Ron Brookmeyer

Ron Brookmeyer

Objective: To evaluate the statistical accuracy of estimates of current HIV incidence rates from cross-sectional surveys, and to identify characteristics of assays that improve accuracy.

Methods: Performed mathematical and statistical analysis of the cross-sectional estimator of HIV incidence to evaluate bias and variance. Developed probability models to evaluate impact of long tails of the window period distribution on accuracy.

Results: The standard cross-sectional estimate of HIV incidence rate is estimating a time-lagged incidence where the lag time, called the shadow, depends on the mean and the coefficient of variation of window periods. Equations show how the shadow increases with the …

Linear Free Energy Relationship Correlations For Room Temperature Ionic Liquids: Revised Cation-Specific And Anion-Specific Equation Coefficients For Predictive Applications Covering A Much Larger Area Of Chemical Space, Laura M. Sprunger, Jennifer Gibbs, Amy Proctor, William E. Acree Jr., Michael H. Abraham, Yunjing Meng, Cong Yao, Jared L. Anderson

Jared L. Anderson

Previously reported ion-specific equation coefficients for both the Abraham general solvation model and Goss modified Abraham model are updated using recently measured activity coefficient, gas chromatographic retention factor, and solubility data for solutes dissolved in room temperature ionic liquids (RTILs). Reported for the first time are equation coefficients for 1-propyl-2,3-dimethylimidazolium cation, and octylsulfate and thiocyanate anions. In total nine sets of cation-specific and eight sets of anion-specific equation coefficients have been determined for each model. The derived correlations describe the 976 experimental gas-to-RTIL partition coefficients to within a standard deviation of 0.12 log units and the 955 experimental water-to-RTIL partitions …

Quantile Regression, Roger Koenker, Kevin F. Hallock

Kevin F Hallock

Quantile regression as introduced by Koenker and Bassett seeks to extend ideas of quantiles to the estimation of conditional quantile functions--models in which quantiles of the conditional distribution of the response variable are expressed as functions of observed covariates.

The Most Representative Composite Rank Ordering Of Multi-Attribute Objects By The Particle Swarm Optimization, Sudhanshu K. Mishra

Sudhanshu K Mishra

Rank-ordering of individuals or objects on multiple criteria has many important practical applications. A reasonably representative composite rank ordering of multi-attribute objects/individuals or multi-dimensional points is often obtained by the Principal Component Analysis, although much inferior but computationally convenient methods also are frequently used. However, such rank ordering – even the one based on the Principal Component Analysis – may not be optimal. This has been demonstrated by several numerical examples. To solve this problem, the Ordinal Principal Component Analysis was suggested some time back. However, this approach cannot deal with various types of alternative schemes of rank ordering, mainly …

Basic Statistics-I, Durgesh Chandra Pathak

Durgesh Chandra Pathak

It's a presentation that I prepared for JRF-students in Development Studies.