8 Matching Results

Search Results

Results: 1 - 8
open access

An Application of Ridge Regression to Educational Research

Description: Behavioral data are frequently plagued with highly intercorrelated variables. Collinearity is an indication of insufficient information in the model or in the data. It, therefore, contributes to the unreliability of the estimated coefficients. One result of collinearity is that regression weights derived in one sample may lead to poor prediction in another model. One technique which was developed to deal with highly intercorrelated independent variables is ridge regression. It was first propose… more
Date: December 1980
Creator: Amos, Nancy Notley
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Comparison of Three Criteria Employed in the Selection of Regression Models Using Simulated and Real Data

Description: Researchers who make predictions from educational data are interested in choosing the best regression model possible. Many criteria have been devised for choosing a full or restricted model, and also for selecting the best subset from an all-possible-subsets regression. The relative practical usefulness of three of the criteria used in selecting a regression model was compared in this study: (a) Mallows' C_p, (b) Amemiya's prediction criterion, and (c) Hagerty and Srinivasan's method involving … more
Date: December 1994
Creator: Graham, D. Scott
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

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

Missing Data Treatments at the Second Level of Hierarchical Linear Models

Description: The current study evaluated the performance of traditional versus modern MDTs in the estimation of fixed-effects and variance components for data missing at the second level of an hierarchical linear model (HLM) model across 24 different study conditions. Variables manipulated in the analysis included, (a) number of Level-2 variables with missing data, (b) percentage of missing data, and (c) Level-2 sample size. Listwise deletion outperformed all other methods across all study conditions in t… more
Date: August 2011
Creator: St. Clair, Suzanne W.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Use Of Effect Size Estimates To Evaluate Covariate Selection, Group Separation, And Sensitivity To Hidden Bias In Propensity Score Matching.

Description: Covariate quality has been primarily theory driven in propensity score matching with a general adversity to the interpretation of group prediction. However, effect sizes are well supported in the literature and may help to inform the method. Specifically, I index can be used as a measure of effect size in logistic regression to evaluate group prediction. As such, simulation was used to create 35 conditions of I, initial bias and sample size to examine statistical differences in (a) post-matchi… more
Date: December 2011
Creator: Lane, Forrest C.
Item Type: Refine your search to only Thesis or Dissertation
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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
Back to Top of Screen