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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
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
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
Partner: UNT Libraries
open access

Convergent Validity of Variables Residualized By a Single Covariate: the Role of Correlated Error in Populations and Samples

Description: This study examined the bias and precision of four residualized variable validity estimates (C0, C1, C2, C3) across a number of study conditions. Validity estimates that considered measurement error, correlations among error scores, and correlations between error scores and true scores (C3) performed the best, yielding no estimates that were practically significantly different than their respective population parameters, across study conditions. Validity estimates that considered measurement e… more
Date: May 2013
Creator: Nimon, Kim
Partner: UNT Libraries
open access

Ability Estimation Under Different Item Parameterization and Scoring Models

Description: A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known item parameters and ability estimates. The item response data sets were submitted to seven dichotomous or polytomous IRT models with different item parameterization to estimate examinee ability. The accur… more
Date: May 2002
Creator: Si, Ching-Fung B.
Partner: UNT Libraries
open access

Establishing the utility of a classroom effectiveness index as a teacher accountability system.

Description: How to identify effective teachers who improve student achievement despite diverse student populations and school contexts is an ongoing discussion in public education. The need to show communities and parents how well teachers and schools improve student learning has led districts and states to seek a fair, equitable and valid measure of student growth using student achievement. This study investigated a two stage hierarchical model for estimating teacher effect on student achievement. This me… more
Date: May 2002
Creator: Bembry, Karen L.
Partner: UNT Libraries
open access

The Supply and Demand of Physician Assistants in the United States: A Trend Analysis

Description: The supply of non-physician clinicians (NPCs), such as physician assistant (PAs), could significantly influence demand requirements in medical workforce projections. This study predicts supply of and demand for PAs from 2006 to 2020. The PA supply model utilized the number of certified PAs, the educational capacity (at 10% and 25% expansion) with assumed attrition rates, and retirement assumptions. Gross domestic product (GDP) chained in 2000 dollar and US population were utilized in a transfer… more
Date: May 2007
Creator: Orcutt, Venetia L.
Partner: UNT Libraries
open access

The Characteristics and Properties of the Threshold and Squared-Error Criterion-Referenced Agreement Indices

Description: Educators who use criterion-referenced measurement to ascertain the current level of performance of an examinee in order that the examinee may be classified as either a master or a nonmaster need to know the accuracy and consistency of their decisions regarding assignment of mastery states. This study examined the sampling distribution characteristics of two reliability indices that use the squared-error agreement function: Livingston's k^2(X,Tx) and Brennan and Kane's M(C). The sampling distri… more
Date: May 1988
Creator: Dutschke, Cynthia F. (Cynthia Fleming)
Partner: UNT Libraries
open access

A Comparison of Three Methods of Detecting Test Item Bias

Description: This study compared three methods of detecting test item bias, the chi-square approach, the transformed item difficulties approach, and the Linn-Harnish three-parameter item response approach which is the only Item Response Theory (IRT) method that can be utilized with minority samples relatively small in size. The items on two tests which measured writing and reading skills were examined for evidence of sex and ethnic bias. Eight sets of samples, four from each test, were randomly selected fro… more
Date: May 1985
Creator: Monaco, Linda Gokey
Partner: UNT Libraries
open access

A State-Wide Survey on the Utilization of Instructional Technology by Public School Districts in Texas

Description: Effective utilization of instructional technology can provide a valuable method for the delivery of a school program, and enable a teacher to individualize according to student needs. Implementation of such a program is costly and requires careful planning and adequate staff development for school personnel. This study examined the degree of commitment by Texas school districts to the use of the latest technologies in their efforts to revolutionize education. Quantitative data were collected by… more
Date: May 1990
Creator: Hiett, Elmer D. (Elmer Donald)
Partner: UNT Libraries
open access

A comparison of the Effects of Different Sizes of Ceiling Rules on the Estimates of Reliability of a Mathematics Achievement Test

Description: This study compared the estimates of reliability made using one, two, three, four, five, and unlimited consecutive failures as ceiling rules in scoring a mathematics achievement test which is part of the Iowa Tests of Basic Skill (ITBS), Form 8. There were 700 students randomly selected from a population (N=2640) of students enrolled in the eight grades in a large urban school district in the southwestern United States. These 700 students were randomly divided into seven subgroups so that each … more
Date: May 1987
Creator: Somboon Suriyawongse
Partner: UNT Libraries
open access

A Comparison of Some Continuity Corrections for the Chi-Squared Test in 3 x 3, 3 x 4, and 3 x 5 Tables

Description: This study was designed to determine whether chis-quared based tests for independence give reliable estimates (as compared to the exact values provided by Fisher's exact probabilities test) of the probability of a relationship between the variables in 3 X 3, 3 X 4 , and 3 X 5 contingency tables when the sample size is 10, 20, or 30. In addition to the classical (uncorrected) chi-squared test, four methods for continuity correction were compared to Fisher's exact probabilities test. The four met… more
Date: May 1987
Creator: Mullen, Jerry D. (Jerry Davis)
Partner: UNT Libraries
open access

Willingness of Educators to Participate in a Descriptive Research Study as a Function of a Monetary Incentive

Description: The problem considered involved assessing willingness of educators to participate in a study offering monetary incentives. Determination of willingness was implemented by sending educators a packet requesting return of a postcard to indicate willingness to participate. The purpose was twofold: to determine the effect of a monetary incentive upon willingness of educators to participate in a research study, and to analyze implications for mail questionnaire studies. A sample of 600 educators was … more
Date: May 1984
Creator: Pittman, Doyle
Partner: UNT Libraries
open access

Effect of Rater Training and Scale Type on Leniency and Halo Error in Student Ratings of Faculty

Description: The purpose of this study was to determine if leniency and halo error in student ratings could be reduced by training the student raters and by using a Behaviorally Anchored Rating Scale (BARS) rather than a Likert scale. Two hypotheses were proposed. First, the ratings collected from the trained raters would contain less halo and leniency error than those collected from the untrained raters. Second, within the group of trained raters the BARS would contain less halo and leniency error than the… more
Date: May 1987
Creator: Cook, Stuart S. (Stuart Sheldon)
Partner: UNT Libraries
open access

A Comparison of Three Correlational Procedures for Factor-Analyzing Dichotomously-Scored Item Response Data

Description: In this study, an improved correlational procedure for factor-analyzing dichotomously-scored item response data is described and tested. The procedure involves (a) replacing the dichotomous input values with continuous probability values obtained through Rasch analysis; (b) calculating interitem product-moment correlations among the probabilities; and (c) subjecting the correlations to unweighted least-squares factor analysis. Two simulated data sets and an empirical data set (Kentucky Comprehe… more
Date: May 1991
Creator: Fluke, Ricky
Partner: UNT Libraries
open access

An Empirical Investigation of Tukey's Honestly Significant Difference Test with Variance Heterogeneity and Equal Sample Sizes, Utilizing Box's Coefficient of Variance Variation

Description: This study sought to determine boundary conditions for robustness of the Tukey HSD statistic when the assumptions of homogeneity of variance were violated. Box's coefficient of variance variation, C^2 , was utilized to index the degree of variance heterogeneity. A Monte Carlo computer simulation technique was employed to generate data under controlled violation of the homogeneity of variance assumption. For each sample size and number of treatment groups condition, an analysis of variance F-tes… more
Date: May 1980
Creator: Strozeski, Michael W.
Partner: UNT Libraries
open access

An Empirical Investigation of Tukey's Honestly Significant Difference Test with Variance Heterogeneity and Unequal Sample Sizes, Utilizing Kramer's Procedure and the Harmonic Mean

Description: This study sought to determine the effect upon Tukey's Honestly Significant Difference (HSD) statistic of concurrently violating the assumptions of homogeneity of variance and equal sample sizes. Two forms for the unequal sample size problem were investigated. Kramer's form and the harmonic mean approach were the two unequal sample size procedures studied. The study employed a Monte Carlo simulation procedure which varied sample sizes with a heterogeneity of variance condition. Four thousand ex… more
Date: May 1976
Creator: McKinney, William Lane
Partner: UNT Libraries
open access

A Comparison of Two Criterion-Referenced Item-Selection Techniques Utilizing Simulated Data with Item Pools that Vary in Degrees of Item Difficulty

Description: The problem of this study was to examine the equivalency of two different types of criterion-referenced item-selection techniques on simulated data as item pools varied in degrees of item difficulty. A pretest-posttest design was employed in which pass-fail scores were randomly generated for item pools of twenty-five items. From the item pools, the two techniques determined which items were to be used to make up twelve-item criterion-referenced tests. The twenty-five items also were rank ordere… more
Date: May 1974
Creator: Davis, Robbie G.
Partner: UNT Libraries
open access

Comparisons of Improvement-Over-Chance Effect Sizes for Two Groups Under Variance Heterogeneity and Prior Probabilities

Description: The distributional properties of improvement-over-chance, I, effect sizes derived from linear and quadratic predictive discriminant analysis (PDA) and from logistic regression analysis (LRA) for the two-group univariate classification were examined. Data were generated under varying levels of four data conditions: population separation, variance pattern, sample size, and prior probabilities. None of the indices provided acceptable estimates of effect for all the conditions examined. There were … more
Date: May 2003
Creator: Alexander, Erika D.
Partner: UNT Libraries
open access

Using Posterior Predictive Checking of Item Response Theory Models to Study Invariance Violations

Description: The common practice for testing measurement invariance is to constrain parameters to be equal over groups, and then evaluate the model-data fit to reject or fail to reject the restrictive model. Posterior predictive checking (PPC) provides an alternative approach to evaluating model-data discrepancy. This paper explores the utility of PPC in estimating measurement invariance. The simulation results show that the posterior predictive p (PP p) values of item parameter estimates respond to various… more
Date: May 2017
Creator: Xin, Xin
Partner: UNT Libraries
open access

Structural Validity and Item Functioning of the LoTi Digital-Age Survey.

Description: The present study examined the structural construct validity of the LoTi Digital-Age Survey, a measure of teacher instructional practices with technology in the classroom. Teacher responses (N = 2840) from across the United States were used to assess factor structure of the instrument using both exploratory and confirmatory analyses. Parallel analysis suggests retaining a five-factor solution compared to the MAP test that suggests retaining a three-factor solution. Both analyses (EFA and CFA) i… more
Date: May 2011
Creator: Mehta, Vandhana
Partner: UNT Libraries
open access

Spatial Ability, Motivation, and Attitude of Students as Related to Science Achievement

Description: Understanding student achievement in science is important as there is an increasing reliance of the U.S. economy on math, science, and technology-related fields despite the declining number of youth seeking college degrees and careers in math and science. A series of structural equation models were tested using the scores from a statewide science exam for 276 students from a suburban north Texas public school district at the end of their 5th grade year and the latent variables of spatial abilit… more
Date: May 2011
Creator: Bolen, Judy Ann
Partner: UNT Libraries
open access

Construct Validation and Measurement Invariance of the Athletic Coping Skills Inventory for Educational Settings

Description: The present study examined the factor structure and measurement invariance of the revised version of the Athletic Coping Skills Inventory (ACSI-28), following adjustment of the wording of items such that they were appropriate to assess Coping Skills in an educational setting. A sample of middle school students (n = 1,037) completed the revised inventory. An initial confirmatory factor analysis led to the hypothesis of a better fitting model with two items removed. Reliability of the subscales a… more
Date: May 2017
Creator: Sanguras, Laila Y., 1977-
Partner: UNT Libraries
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