We provide tools for identification and exploration of data with very large variability having power law tails. Such data describe extreme features of processes such as fire losses, flood, drought, financial gain/loss, hurricanes, population of cities, among others. Prediction and quantification of extreme events are at the forefront of the…

Two subtypes of dyslexia (phonological, visual) have been under debate in various studies. However, the number of symptoms of dyslexia described in the literature exceeds the number of subtypes, and underlying relations remain unclear. We investigated underlying cognitive features of dyslexia with exploratory and confirmatory factor analyses. A…

Learning effectiveness requires an understanding of the relationship among extracurricular activities, learning approach and academic performance and, it is argued, this helps educators develop techniques designed to enrich learning effectiveness. Biggs' Presage-Process-Product model on student learning has identified the relationship among…

We extend to the longitudinal setting a latent class approach that was recently introduced by Lanza, Coffman, and Xu to estimate the causal effect of a treatment. The proposed approach enables an evaluation of multiple treatment effects on subpopulations of individuals from a dynamic perspective, as it relies on a latent Markov (LM) model that is…

A theoretical model linking boredom and academic achievement is proposed. Based on Pekrun's (2006) control-value theory of achievement emotions, the model posits that boredom and achievement reciprocally influence each other over time. Data from a longitudinal study with college students (N = 424) were used to examine the hypothesized effects. The…

Although research suggests an interplay between identity development and self-esteem, most studies focused on the role of identity commitment and measured only level of self-esteem. This study examined longitudinal associations between Berzonsky's (2011) styles of identity exploration and two distinct features of self-esteem: level of self-esteem…

The regression discontinuity (RD) design (Thistlewaite & Campbell, 1960; Cook, 2008) provides a framework to identify and estimate causal effects from a non-randomized design. Each subject of a RD design is assigned to the treatment (versus assignment to a non-treatment) whenever her/his observed value of the assignment variable equals or…

This paper investigates the main indicators of scores of K-12 leavers who were admitted at Princess Sumaya University for Technology, PSUT, in Jordan and their graduation scores. It uses time series data covering the period 1993-2012, including all 3,229 Bachelor graduates in all specialisations. The paper applies several statistical techniques to…

To assess the value of individual students' subscores on the Major Field Test in Business (MFT Business), I examined the test's internal structure with factor analysis and structural equation model methods, and analyzed the subscore reliabilities using the augmented scores method. Analyses of the internal structure suggested that the MFT Business…

Karabatsos and Walker (2011) introduced a new Bayesian nonparametric (BNP) regression model. Through analyses of real and simulated data, they showed that the BNP regression model outperforms other parametric and nonparametric regression models of common use, in terms of predictive accuracy of the outcome (dependent) variable. The other,…

Remedial or developmental courses are the most common policy instruments used to assist underprepared postsecondary students who are not ready for college-level coursework. However, despite its important role in higher education and its substantial costs, there is little rigorous evidence on the effectiveness of college remediation on the outcomes…