A comparison of traditional and IRT factor analysis.

A comparison of traditional and IRT factor analysis.

Date: December 2004
Creator: Kay, Cheryl Ann
Description: This study investigated the item parameter recovery of two methods of factor analysis. The methods researched were a traditional factor analysis of tetrachoric correlation coefficients and an IRT approach to factor analysis which utilizes marginal maximum likelihood estimation using an EM algorithm (MMLE-EM). Dichotomous item response data was generated under the 2-parameter normal ogive model (2PNOM) using PARDSIM software. Examinee abilities were sampled from both the standard normal and uniform distributions. True item discrimination, a, was normal with a mean of .75 and a standard deviation of .10. True b, item difficulty, was specified as uniform [-2, 2]. The two distributions of abilities were completely crossed with three test lengths (n= 30, 60, and 100) and three sample sizes (N = 50, 500, and 1000). Each of the 18 conditions was replicated 5 times, resulting in 90 datasets. PRELIS software was used to conduct a traditional factor analysis on the tetrachoric correlations. The IRT approach to factor analysis was conducted using BILOG 3 software. Parameter recovery was evaluated in terms of root mean square error, average signed bias, and Pearson correlations between estimated and true item parameters. ANOVAs were conducted to identify systematic differences in error indices. Based on many ...
Contributing Partner: UNT Libraries
An Exploration of the Ground Water Quality of the Trinity Aquifer Using Multivariate Statistical Techniques

An Exploration of the Ground Water Quality of the Trinity Aquifer Using Multivariate Statistical Techniques

Date: August 2011
Creator: Holland, Jennifer M.
Description: The ground water quality of the Trinity Aquifer for wells sampled between 2000 and 2009 was examined using multivariate and spatial statistical techniques. A Kruskal-Wallis test revealed that all of the water quality parameters with the exception of nitrate vary with land use. A Spearman’s rho analysis illustrates that every water quality parameter with the exception of silica correlated with well depth. Factor analysis identified four factors contributable to hydrochemical processes, electrical conductivity, alkalinity, and the dissolution of parent rock material into the ground water. The cluster analysis generated seven clusters. A chi-squared analysis shows that Clusters 1, 2, 5, and 6 are reflective of the distribution of the entire dataset when looking specifically at land use categories. The nearest neighbor analysis revealed clustered, dispersed, and random patterns depending upon the entity being examined. The spatial autocorrelation technique used on the water quality parameters for the entire dataset identified that all of the parameters are random with the exception of pH which was found to be spatially clustered. The combination of the multivariate and spatial techniques together identified influences on the Trinity Aquifer including hydrochemical processes, agricultural activities, recharge, and land use. In addition, the techniques aided in identifying areas ...
Contributing Partner: UNT Libraries
Identification of Remote Leadership Patterns in Academic and Public Libraries

Identification of Remote Leadership Patterns in Academic and Public Libraries

Date: August 2008
Creator: Venetis, Mary Jo
Description: Seminal works on leadership, including those in librarianship define a traditional model of interaction between leaders and followers without reference to the information technology-driven environment. In addition, remote leadership indicates a different model from the traditional model, one that is focused on the interaction of leaders and their staff through digital technology. Although leaders still use face-to-face interaction, due to varied work schedules or job responsibilities, they also recognize the need to lead employees remotely. Leadership studies in library literature have not addressed how library leaders use information technology to lead employees remotely, nor have these studies addressed remote leadership and remote employees, except for some articles on telecommuting. As a result, this research was conducted to address this gap, providing an exploratory foundation of emergent patterns of remote leadership with its associated leadership dimensions rooted in personality traits, behaviors, and skills. Quantitative and qualitative data were obtained from a small sample size of academic and public-library leaders in the United States who participated in a Web-based survey designed specifically for this study, limiting generalizations. Factor analysis was the principal methodology used to obtain findings. Its composite factor scores were also used in the t-test and chi-square analyses. This study ...
Contributing Partner: UNT Libraries
Factor Structure of the Neurocognitive Battery in a Geriatric Sample with Cognitive Impairments

Factor Structure of the Neurocognitive Battery in a Geriatric Sample with Cognitive Impairments

Date: May 2007
Creator: Serova, Svetlana
Description: The present study was designed to empirically validate six theoretically derived cognitive domains (verbal memory, visual memory, working memory, attention-concentration, executive functions, and visuospatial abilities) assessed by a comprehensive battery of neuropsychological tests used in the Geriatric Memory Clinic at the University of North Texas Health Science Center in Fort Worth, Texas. The study examined the extent to which various cognitive dimensions are tapped by this battery in a heterogeneous geriatric sample of 114 patients with cognitive impairments. The proposed six-factor model of cognitive functioning has not been supported. Further exploratory factor analysis arrived at a five-factor solution. Factor pattern of the 23 tests supported the following five dimensions: memory, executive control, attention, visuospatial abilities, and cognitive flexibility.
Contributing Partner: UNT Libraries
Latent Semantic Analysis: Five methodological recommendations

Latent Semantic Analysis: Five methodological recommendations

Date: 2012
Creator: Evangelopoulos, Nicholas; Zhang, Xiaoni & Prybutok, Victor R.
Description: Article discussing latent semantic analysis and five methodological recommendations.
Contributing Partner: UNT College of Business
The Development and Assessment of an Instrument for Measuring Mental Model Styles in Korea

The Development and Assessment of an Instrument for Measuring Mental Model Styles in Korea

Date: 2012
Creator: Chermack, Thomas J.; Song, Ji Hoon; Nimon, Kim F.; Choi, Myungweon & Korte, Russel F.
Description: This article discusses a research study on the development and assessment of an instrument for measuring mental model styles in Korea.
Contributing Partner: UNT College of Information