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Outliers and Regression Models

Description: The mitigation of outliers serves to increase the strength of a relationship between variables. This study defined outliers in three different ways and used five regression procedures to describe the effects of outliers on 50 data sets. This study also examined the relationship among the shape of the distribution, skewness, and outliers.
Date: May 1992
Creator: Mitchell, Napoleon
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Mathematical Programming Approaches to the Three-Group Classification Problem

Description: In the last twelve years there has been considerable research interest in mathematical programming approaches to the statistical classification problem, primarily because they are not based on the assumptions of the parametric methods (Fisher's linear discriminant function, Smith's quadratic discriminant function) for optimality. This dissertation focuses on the development of mathematical programming models for the three-group classification problem and examines the computational efficiency an… more
Date: August 1993
Creator: Loucopoulos, Constantine
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Determination of the Optimal Number of Strata for Bias Reduction in Propensity Score Matching.

Description: Previous research implementing stratification on the propensity score has generally relied on using five strata, based on prior theoretical groundwork and minimal empirical evidence as to the suitability of quintiles to adequately reduce bias in all cases and across all sample sizes. This study investigates bias reduction across varying number of strata and sample sizes via a large-scale simulation to determine the adequacy of quintiles for bias reduction under all conditions. Sample sizes rang… more
Date: May 2010
Creator: Akers, Allen
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Simulation Study Comparing Various Confidence Intervals for the Mean of Voucher Populations in Accounting

Description: This research examined the performance of three parametric methods for confidence intervals: the classical, the Bonferroni, and the bootstrap-t method, as applied to estimating the mean of voucher populations in accounting. Usually auditing populations do not follow standard models. The population for accounting audits generally is a nonstandard mixture distribution in which the audit data set contains a large number of zero values and a comparatively small number of nonzero errors. This study … more
Date: December 1992
Creator: Lee, Ihn Shik
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Generalization of the Logistic Discriminant Function Analysis and Mantel Score Test Procedures to Detection of Differential Testlet Functioning

Description: Two procedures for detection of differential item functioning (DIF) for polytomous items were generalized to detection of differential testlet functioning (DTLF). The methods compared were the logistic discriminant function analysis procedure for uniform and non-uniform DTLF (LDFA-U and LDFA-N), and the Mantel score test procedure. Further analysis included comparison of results of DTLF analysis using the Mantel procedure with DIF analysis of individual testlet items using the Mantel-Haenszel (… more
Date: August 1994
Creator: Kinard, Mary E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Effect of Psychometric Parallelism among Predictors on the Efficiency of Equal Weights and Least Squares Weights in Multiple Regression

Description: There are several conditions for applying equal weights as an alternative to least squares weights. Psychometric parallelism, one of the conditions, has been suggested as a necessary and sufficient condition for equal-weights aggregation. The purpose of this study is to investigate the effect of psychometric parallelism among predictors on the efficiency of equal weights and least squares weights. Target correlation matrices with 10,000 cases were simulated so that the matrices had varying degr… more
Date: May 1996
Creator: Zhang, Desheng
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Measurement Disturbance Effects on Rasch Fit Statistics and the Logit Residual Index

Description: The effects of random guessing as a measurement disturbance on Rasch fit statistics (unweighted total, weighted total, and unweighted ability between) and the Logit Residual Index (LRI) were examined through simulated data sets of varying sample sizes, test lengths, and distribution types. Three test lengths (25, 50, and 100), three sample sizes (25, 50, and 100), two item difficulty distributions (normal and uniform), and three levels of guessing (no guessing (0%), 25%, and 50%) were used in t… more
Date: August 1997
Creator: Mount, Robert E. (Robert Earl)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Data Annex to the United Nations Truth Commission on the civil war in El Salvador from 1979--1991 (digitized text)

Description: This dataset contains statistical information transcribed from the supplementary documentation of a United Nations (UN) report compiled by The Commission on the Truth for El Salvador (La Comision de la Verdad para El Salvador). It includes information about approximately 20,000 civilian/noncombatant victims of the civil war in El Salvador (from 1979 to 1991) taken from interviews of those who survived or knew/knew of those who were victims.
Date: October 2012
Creator: Mason, T. David; Hamner, Jesse & Phillips, Mark Edward
Item Type: Refine your search to only Dataset
Partner: UNT Libraries
open access

Attenuation of the Squared Canonical Correlation Coefficient Under Varying Estimates of Score Reliability

Description: Research pertaining to the distortion of the squared canonical correlation coefficient has traditionally been limited to the effects of sampling error and associated correction formulas. The purpose of this study was to compare the degree of attenuation of the squared canonical correlation coefficient under varying conditions of score reliability. Monte Carlo simulation methodology was used to fulfill the purpose of this study. Initially, data populations with various manipulated conditions wer… more
Date: August 2010
Creator: Wilson, Celia M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Spatial Analysis of Teen Births in North Central Texas

Description: The United States has the highest teen birth rate among western industrialized countries and the highest levels of pregnancy among adolescents (Alan Guttmacher Institute, 1994). While the rate of teen births is high throughout the country, considerable variations exist between and within regions. Texas is one of the 5 leading states with the highest teen birth rates to mothers less than 18 years of age. This research provides a detailed analysis of births to mothers aged between 10 and 19 years… more
Date: December 2001
Creator: Donkor, Faustina Fosua
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

An entropic approach to the analysis of time series.

Description: Statistical analysis of time series. With compelling arguments we show that the Diffusion Entropy Analysis (DEA) is the only method of the literature of the Science of Complexity that correctly determines the scaling hidden within a time series reflecting a Complex Process. The time series is thought of as a source of fluctuations, and the DEA is based on the Shannon entropy of the diffusion process generated by these fluctuations. All traditional methods of scaling analysis, instead, are base… more
Date: December 2001
Creator: Scafetta, Nicola
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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