Physical Sciences and Mathematics Commons^™

Averaged Motion Of Charged Particles In A Curved Strip, Avner Friedman, Chaocheng Huang

Mathematics and Statistics Faculty Publications

This paper is concerned with the motion of electrically charged particles in a "curved" infinite strip.

On The Product Of Two Generalized Derivations, Mohamed Barraa, Steen Pedersen

Mathematics and Statistics Faculty Publications

Two elements A and B in a ring R determine a generalized derivation delta_A,B on R by setting δ_A,B(X) = AX - XA for any X in R. We characterize when the product δ_C,Dδ_A,B is a generalized derivation in the cases when the ring R is the algebra of all bounded operators on a Banach space epsilon, and when R is a C*-algebra U. We use the se characterizations to compute the commutant of the range of δ_A,B.

Is Chapter 11 Too Favorable To Debtors? Evidence From Abroad, Theodore Eisenberg, Stefan Sundgren

Cornell Law Faculty Publications

Chapter 11 is widely believed to be among the industrialized world's most debtor-oriented reorganization laws. Critics assert that Chapter 11 is too easily available and that it allows debtors too much control by, inter alia, not requiring appointment of a trustee. One criticism of Chapter 11, low returns to unsecured creditors, resonates with an important theme of this Symposium, the Bebchuk-Fried proposal to reduce secured creditor priority in insolvency proceedings. The Chapter 11 criticisms and the Bebchuk-Fried proposal raise the question whether less easy access to Chapter 11, reduced debtor control, diminished secured creditor priority, or other changes could reduce …

Hypersurfaces In R-D And The Variance Of Exit Times For Brownian Motion, Kimberly Kinateder, Patrick Mcdonald

Mathematics and Statistics Faculty Publications

Using the first exit time for Brownian motion from a smoothly bounded domain in Euclidean space, we define two natural functionals on the space of embedded, compact, oriented, unparametrized hypersurfaces in Euclidean space. We develop explicit formulas for the first variation of each of the functionals and characterize the critical points.

Seasonal Adjustment Of Naira Exchange Rate Statistics 1970-1995, O M. Akinuli

CBN Occasional Papers

This paper uses a current statistical approach to examine and adjust the seasonalities in the Naira exchange rate statistics, vis-a-vis the U.S. Dollar and the pound sterling for a period of twenty-five (25) years. Such study is necessary as it helps to understand the behavioural pattern of a trend in an attempt to predict the future. An investigation like this also helps to expose both the short and long run tendencies of a series which may require urgent or new policy measures to be taken sooner than expected. This paper reviews the regimes of exchange rate under the period, the …

Mark-Recapture Creel Survey And Survival Models, Shampa Saha

Mathematics & Statistics Theses & Dissertations

In this dissertation, we consider a model based approach to the estimation of exploitation rate of a fish population by combining mark-recapture procedures with a creel survey. We also consider the analysis of a proportional hazards survival model for randomly censored observations, known as the Koziol-Green model. The model assumes that the lifetime survivor function is a power of the censored time survivor function.

In Chapter 2, we introduce the model based approach to the estimation of the exploitation rate of a fish population by combining mark-recapture procedures with a creel survey. We assume that in the beginning of a …

The Predictability Of Punitive Damages, Theodore Eisenberg, John Goerdt, Brian Ostrom, David Rottman, Martin T. Wells

Cornell Law Faculty Publications

Using one year of jury trial outcomes from 45 of the nation's most populous counties, this article shows a strong and statistically significant correlation between compensatory and punitive damages. These findings are replicated in 25 years of punitive damages awards from Cook County, Illinois, and California. In addition, we find no evidence that punitive damages awards are more likely when individuals sue businesses than when individuals sue individuals. With respect to award frequency, juries rarely award punitive damages and appear to be especially reluctant to do so in the areas of law that have captured the most attention, products liability …

Using Ranks To Perform Exact And Estimated Exact Tests In Designed Experiments, Scott J. Richter, Mark E. Payton

Conference on Applied Statistics in Agriculture

A procedure is studied that uses rank transformed data to perform exact and estimated exact tests which is an alternative to the commonly used F-ratio test procedure. First, a common parametric test statistic is computed using rank transformed data, where two methods of ranking - ranks taken of the original observations, and ranks taken after aligning the observations - are studied. Significance is then determined using either the exact permutation distribution of the statistic or an estimate of this distribution based on a random sample of all possible permutations. Simulation studies compare the performance of this method to both the …

Testing Variance Components Using The Glm And Mixed Procedures Of Sas®, Ron Mcnew, Andy Mauromoustakos

Conference on Applied Statistics in Agriculture

The test of a variance component in random and mixed normal linear models can be done using the F statistic from the analysis of variance or the Wald statistic which is the ratio of the variance component estimate to its estimated standard error. These are the methods used in the GLM and MIXED procedures of SAS®. We show that these two tests can give different results on the same data. For the one-way random model, the one-sided Wald test on the among group variance component can never be significant at the 0.05 probability level when the number of levels of …

The Statistical Analysis Of Active Control Equivalence Studies, Armando Garsd, Susana F. Delfino

Conference on Applied Statistics in Agriculture

In experimental work, the notion of equivalence falls short of the idea of equality. Thus, the effects of two treatments, while not identical, may still be regarded as equivalent if their difference is negligible in a certain sense. This simple distinction raises not only technical difficulties, since of necessity it results in special statistical procedures, but also deeper conceptual issues, since one has to ask why two treatments should be equivalent but not equal, more specifically, whether their being merely equivalent has any bearing on the practical questions posed by the data. In this paper we present examples, drawn from …

The Analysis Of The Two-Period Repeated Measurements Crossover Design With Application To A Forestry Problem, Armando Garsd, Maria C. Fabrizio, Maria V. López

Conference on Applied Statistics in Agriculture

The two-period repeated measurements crossover design is not often used in agricultural studies. It is, however, an attractive model, involving the confluence of two powerful statistical ideas, treatment crossover and repeated measurements on the same experimental unit. This paper presents one approach for the statistical analysis of such design based on the work of Wallenstein and Fisher (1977). It is shown how the data may be transformed so that it can be analyzed under the framework of a completely randomized repeated measurements design. We formalize the analysis in the context of a forestry experiment conducted on poplar trees (Populus SP.), …

The Use Of Inverse Theory On An Ill-Posed Environmental Composite Sampling Problem, V. A. Lancaster, S. Keller-Mcnulty

Conference on Applied Statistics in Agriculture

As an alternative to retesting, the use of inverse theory techniques is proposed to resolve the lack of information inherent in composite sampling methods. This paper evaluates the feasibility of combining composite sampling with the inverse theory technique of linear regularization on an environmental site characterization investigation. Federal legislation has mandated the cleanup of hazardous waste sites, creating the need to characterize these sites for various chemical constituents. An abundance of samples, high measurement costs, and limited budgets create the appeal of compositing samples. We propose that the number of costly laboratory analyses can be reduced by combining composite sampling …

Bootstrap Confidence Intervals From Adaptive Sampling Of An Insect Population, Jeffrey S. Pontius, Mary C. Christman

Conference on Applied Statistics in Agriculture

We construct 90% normal, percentile, and bias-corrected and accelerated confidence intervals using a finite population bootstrapping algorithm based on adaptive sampling in an agroecosystem. We evaluate the interval estimates based on sampling simulations of a spatially arranged population of plots that contain counts of beet webworms and based on an adaptive condition that generates small networks. The sampling distributions of the original sample estimates and of the bootstrap estimates were generally similar and symmetric. The simulation coverages were from 84% to 90% and similar under any of the sample sizes and any of the three confidence interval types. This study …

Some Experiences With Neural Networks, Lynda L. Ballou, Dallas E. Johnson

Conference on Applied Statistics in Agriculture

This paper gives a brief overview of artificial neural networks which may be used to model data similar to the kind where one usually considers regression models. Many practitioners believe that neural networks perform better than regression models for prediction purposes. Some simulations were performed using three different neural net programs, namely Braincel, Ripley's S+ program, and Nychka's S+ program. These simulations reveal some interesting aspects of neural net programs which should be of interest to anyone considering the use of neural net programs to model continuous data.

Some Factors Limiting The Use Of Generalized Linear Models In Agricultural Research, Walter W. Stroup

Conference on Applied Statistics in Agriculture

The generalized linear model (GLM) is a "hot" topic in statistics. Numerous research articles on GLM's appear in each edition of all major journals in statistics. GLM's are the subject of substantial numbers of presentations at most statistics conferences. Despite the high level of interest and research activity within the statistics community, GLM's are not widely used, with some exceptions, by biological scientists in the statistical analysis of their research data. Why? Reasons include 1) many statisticians are not comfortable with GLM's, 2) the biological research community is not familiar with GLM's, and 3) there is little in introductory statistics …

How Good Are Spatial Glm's? A Simulation Study, Roger G. Collins, Walter W. Stroup, Stephen D. Kachman

Conference on Applied Statistics in Agriculture

An area of increasing interest to agricultural and ecological researchers is the analysis of spatially correlated non-normal data. A generalized linear model(GLM) accounting for spatial covariance was presented by Gotway and Stroup (1997). Their method included approximate inference based on asymptotic distributions. A simulation study was conducted to assess the small sample behavior of their proposed estimates and test statistics. This study suggests that the spatial GLM yields unbiased estimates of treatment means and differences for binomial data, that the spatial GLM improves precision, as measured by MSE, and that the approximate F-statistic is acceptable for hypothesis testing.

Alternative Analyses Of Crossover Designs With More Than Two Periods, Carla L. Goad, Dallas E. Johnson

Conference on Applied Statistics in Agriculture

A crossover experiment is a special form of a repeated measures experiment. An appropriate analysis of a repeated measures experiment depends on the form of the varian-cecovariance matrix of the repeated measures. Certain forms of this matrix yield valid analysis of variance F -tests while other forms invalidate these tests. In a crossover experiment where analysis of variance tests are invalid, two alternative tests of a linear contrast of the parameters are proposed. In addition to these approximate t-tests, three alternative methods for testing for equal treatment effects and equal carryover effects are proposed. A simulation study is conducted to …

Bioavailability And Cv Component Comparison In A Crossover, Zhiming Wang, Vince A. Uthoff

Conference on Applied Statistics in Agriculture

Two medication formulations are compared using noncompartmental pharmacokinetic (PK) variables. However, more than the ratio of mean effects is of interest. A difference in formulation coeficients of varication (CV), within- or between-subject, is sought. The experimental design chosen is a 2 sequence crossover design of the form ABBA and BAAB, where A and B are two medication formulations. A mixed linear model is defined that contains random effects for subjects and for subject by formulation interactions. The model has fixed effects for the average formulation effects and period effects. The 2 formulations are assumed to have different error terms. The …

Equivalence Testing In Agriculture Experiments, Brian J. Fergen

Conference on Applied Statistics in Agriculture

Equivalence testing is a relatively new area of research in statistics. It's development has been motivated in large part by the need for statistical methods for determining if generic drugs are bioequivalent to their name brand counterparts. The application of equivalence testing methods to data resulting from experiments and surveys unrelated to drug development, and in particular agriculture-related experiments, is infrequent and possibly non-existent. These methods provide useful alternatives to the analysis methods currently being used. In this paper, an overview of the philosophy of equivalence testing and a review of equivalence testing methods are presented. Additionally, experimental situations for …

Covariance Adjustment In Studies Involving Observational Factors Or Covariates Influenced By Treatments, O. B. Allen, I. B. Mandell, J. W. Wilton, L. B. Buchanan-Smith

Conference on Applied Statistics in Agriculture

We extend the definition of adjusted treatment means in the analysis of covariance to deal with the case where some of the covariates are influenced by treatments or where some of the factors are observational. In these cases, comparison of treatment means adjusted to a common value of the covariate may be inappropriate. Partially adjusted means are defined and it is shown that special cases include the usual adjusted means (adjusted to a common value for each of the covariates) and unadjusted means. In fact, in a multifactorial experiment, one can, by appropriate choice of adjustment, compare adjusted means for …

Comparing The Use Of Block And Covariate Information In Analysis Of Variance, James R. Schwenke

Conference on Applied Statistics in Agriculture

Of primary concern in the statistical analysis of the results of an experiment is to quantify the mean response to treatment and to accurately quantify the experimentation error variance. The traditional approach to account for nuisance sources of variation or a heterogeneous population is to group or block the population (or sample) into homogeneous groups with respect to a concomitant variable. A blocking term then is included in the statistical analysis. Alternatively, concomitant variables can be used as covariate information in a statistical analysis. A statistical analysis incorporating blocks assumes that the magnitude of difference in treatment response is equal …

Analysis Of A Midwest Farmer Survey Of Pest Infestation, Susanne Aref

Conference on Applied Statistics in Agriculture

A survey of farmers rating the severity of crop pest infestation in their fields was conducted in the Midwest in 1992. The purpose of the present study was to detennine summary variables of the pest infestation ratings and the effect of region, soil type, and tillage on these summary variables. The pests were in the following six categories: perennial and annual weeds, insects and diseases of com (Zea mays L.) and insects and diseases of soybean (Glycine max (L.) MerritT). Categorical models were used to analyze individual pest ratings. A non-parametric method, the Sheirer-Ray-Hare extension of the Kruskal-Wallis test …

Empirical Estimates Of Power For Binomial Data With Mixed Models, R. K. Splan, L. D. Van Vleck, H. D. Hafs

Conference on Applied Statistics in Agriculture

Observations on return to estrus from anestrus postpartum beef cows were used as the basis for a simulation study to develop a method to determine numbers of locations and animals per treatment per location to achieve a specified power of test. Estimates of among location and total variance were obtained by REML from the data set and then used to generate simulated data for the binomial trait. Each combination of several pre-determined factors was replicated 1000 times. Pre-determined factors were number of locations, number of animals per treatment per location, desired detectable difference due to treatment, alpha-probability level and ratio …

Alternative Procedures For Estimation Of Nonlinear Regression Parameters, William J. Price, Bahman Shafii

Conference on Applied Statistics in Agriculture

Biological research data are often represented using nonlinear model specifications that lend themselves to the testing of relevant hypotheses concerning the model parameters. This is typically achieved with classical nonlinear least squares techniques such as Gauss-Newton or Levenberg-Marquardt which allow for both the estimation and inference phases of the analysis. Under some circumstances, however, sensitivity to data or model specifications may lead these methods to fail convergence tests or exhibit nonlinearity in the parameter estimates, which will in turn limit the usefulness of inferential results. In such cases, other estimation methods may present a means of avoiding these problems while …

Confidence Intervals For Heritability In A Mixed Linear Model, Brent D. Burch, Hari K. Iyer

Conference on Applied Statistics in Agriculture

A family of procedures is given to construct confidence intervals for the heritability of a trait in a mixed linear model. The procedures are applicable for constructing confidence intervals for a ratio of variance components in a mixed linear model having two sources of variation. The resulting intervals are evaluated in terms of expected length. The investigator may select the best confidence interval procedure from the family of procedures based on the interval( s) having short expected length. Confidence intervals for loineye data using bulls from a Red Angus seed stock herd will be presented.

Using Prior Knowledge Of The Intraclass Correlation To Increase The Power Of Tests For Treatment Means, Marjorie E. Bond, James J. Higgins

Conference on Applied Statistics in Agriculture

It is common in agricultural research to have experimental units that consist of multiple observational units. For instance, treatments may be applied to pens of animals, pens being the experimental units, while weights are measured on individual animals, the observational units. If there are a small number of experimental units, the power of statistical tests for treatment effects can be small regardless of the number of observational units. We show that it is possible to increase the power of such statistical tests by taking advantage of prior knowledge of the intraclass correlation. Our assertion is that such prior knowledge is …

Analysing Binary Data In A Repeated Measurements Setting Using Sas, Eleanor F. Allan

Conference on Applied Statistics in Agriculture

Whilst the repeated measurements methods appropriate for the analysis of normally distributed data are well established, methods for handling binary and categorical data in a repeated measurements context are not so commonly known or used. The application of population averaged models and subject effects models to repeated binary data are discussed and their implementation with the aid of SAS are illustrated by example. comparisons with other approaches are also considered.

Editor's Preface, Table Of Contents, And List Of Attendees, George A. Milliken

Conference on Applied Statistics in Agriculture

These proceedings contain papers presented in the ninth annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 27-29, 1997.

A Comparison Of Circular Error Probable Estimators For Small Samples, Charles E. Williams

Theses and Dissertations

Several previous studies investigated the performance of competing circular error probable (CEP) estimators for small samples. This estimation is important in ICBM analysis because, due to expense, there are a limited number of ICBM test launches. In the most recent previous study (1993), Tongue considered five CEP estimators in a simulation test, attempting to determine the behavior of these estimators for populations of various bias, ellipticity, correlation, and sample size. In this paper, we build on Tongue's findings in three ways: (1) The number of estimators compared is expanded to eight. (2) Different factors and factor levels are used. (3) …

Experiments In Aggregating Air Ordnance Effectiveness Data For The Tacwar Model, James E. Parker

Theses and Dissertations

An interactive MS Access&trademark; based application that aggregates the output of the SABSEL model for input into the TACWAR model is developed. The application was developed following efforts to create a functional approximation of the SABSEL data using neural networks, statistical networks, and traditional statistical techniques. These approximations were compared to a look-up table methodology on the basis of accuracy, (RMSE