Gülhayat Gölbaşı Şimşek

McDonald's ωt, Cronbach's α, and Generalized θ for Composite Reliability of Common Factors Structures

In the common factor model for subtest scores, several reliability coefficients, including Cronbachs α, have been found to be biased. In this article, we introduce a new coefficient, θG, or Generalized θ, which is a generalized version of Armors θ coefficient and is equal to the true reliability when the dimensions are orthogonal and the measures are parallel. We assessed the McDonalds ωt, α, and θG in terms of mean bias, efficiency, and precision using a Monte Carlo simulation. θG outperformed ωt when the factors were orthogonal or nearly orthogonal with low correlations between them.

Impact Score Technique for Analyzing the Service Quality of a High-Speed Rail System

This paper presents the results of a survey conducted to measure the service quality of the high-speed railway system (HSRS) that operates between two cities in Turkey. The analysis had its basis in the impact score technique. The survey was prepared to ask users for satisfaction ratings of 61 attributes, which were constructed for the seven dimensions of service quality for public transportation systems: passenger information, fare level and type, accessibility, station environment, vehicle environment, service delivery, and security. Through analysis of the results, the most problematic areas of the service provided by the HSRS were determined. According to the model results, the operator of the system should provide enhancements especially in the seat design of the vehicles and also regarding the time and the frequency of the service provided.

An Application of Fuzzy Clustering on Prevalence of Youth Tobacco Survey

Abstract The foremost avoidable cause of disease and death is tobacco consume in almost every country and nearly all tobacco consume begins during youth and young adulthood. The use of tobacco products has increased in years and nearly half of tobacco consumers use more than two tobacco products. The paper is about the application of fuzzy clustering on the data of young peoples attitude toward tobacco products. Fuzzy clustering was used to cluster people into a number of groups based on their use, tendency and intention. In our experiments, we used Fuzzy C-Means algorithms and it was calculated by using R Studios packages. In our analysis, we have considered 7 questions from National Youth Tobacco Survey 2013 Questionnaire. Questions are about use of different tobacco products and thoughts about tobacco. We examined 267 subjects who were randomly selected. As a result of our analysis we came to the conclusion that most young people are not interested in smoking any kind of tobacco products. Most of them have not tried any kind of tobacco but some of them have tendency to smoke in years.

Parallel analysis approach for determining dimensionality in canonical correlation analysis

ABSTRACT Canonical correlations are maximized correlation coefficients indicating the relationships between pairs of canonical variates that are linear combinations of the two sets of original variables. The number of non-zero canonical correlations in a population is called its dimensionality. Parallel analysis (PA) is an empirical method for determining the number of principal components or factors that should be retained in factor analysis. An example is given to illustrate for adapting proposed procedures based on PA and bootstrap modified PA to the context of canonical correlation analysis (CCA). The performances of the proposed procedures are evaluated in a simulation study by their comparison with traditional sequential test procedures with respect to the under-, correct- and over-determination of dimensionality in CCA.