Multivariate count data is ubiquitous in many areas of research including the physical, biological, and social sciences. These data are traditionally modeled with the Dirichlet Multinomial distribution (DM). A new, more flexible Dirichlet-Tree Multinomial (DTM) model is gaining in popularity. Here, we consider Bayesian DTM regression models. Our…

Psychology research often focuses on interactions, and this has deep implications for inference from non-representative samples. For the goal of estimating average treatment effects, we propose to fit a model allowing treatment to interact with background variables and then average over the distribution of these variables in the population. This…

In this paper, we provide an introduction to the factored regression framework. This modeling framework applies the rules of probability to break up or "factor" a complex joint distribution into a product of conditional regression models. Using this framework, we can easily specify the complex multivariate models that missing data…

A latent multivariate regression model is developed that employs a generalized asymmetric Laplace (GAL) prior distribution for regression coefficients. The model is designed for high-dimensional applications where an approximate sparsity condition is satisfied, such that many regression coefficients are near zero after accounting for all the model…

One econometric rule of thumb is that greater dispersion in observations of the independent variable improves estimates of regression coefficients and therefore produces better results, i.e., lower standard errors of the estimates. Nevertheless, students often seem to mistrust precisely the observations that contribute the most to this greater…

Since Merton's classical analysis of cumulative advantage in science, it has been observed that status hierarchies display a sizable disconnect between actors' quality and rank and that they become increasingly asymmetric over time, without, however, turning into winner-take-all structures. In recent years, formal models of status hierarchies…

Engaging students in active learning can enhance their understanding and appreciation of a subject such as statistics. Classroom activities and projects help to engage students and further promote the learning process. In this paper, an activity investigating the influence of population size and wealth on the medal counts from the 2012 London…

In light of the emergence of statistical analysis techniques based on data mining in education sciences, and the potential they offer to detect non-trivial information in large databases, this paper presents a procedure used to detect factors linked to academic achievement in large-scale assessments. The study is based on a non-experimental,…

In recent years educational organizations have begun to be administered by more sharing, participation and democratic principles. The school-based management approach accelerated during the decentralization period in education is also seen as a cause for spread of leadership throughout the school. This trend is reflected in the educational…

As strengths-based approaches continue to gain steady momentum in colleges and universities, a distinct need for scholarship on the benefits of strengths-based practices has emerged. In fall 2011, all first-year students at a university in the Midwest were invited to discover their strengths by taking the Clifton StrengthsFinder. The purpose of…

This large-scale, longitudinal study examines teacher attrition data from over 6,500 teachers in Illinois over a 14-year period from 1997 to 2010. Attrition rates between teachers who participated in a Professional Development School (PDS) versus students prepared traditionally are compared. The effects of teacher preparation experiences on…

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This seventh installment of "Explorations in Statistics" explores regression, a technique that estimates the nature of the relationship between two things for which we may only surmise a mechanistic or predictive…

The study examined the role of motivation in students' performance and engagement in elementary and middle school physical education. Cross-lagged relationships between performance and engagement were investigated across Grades 6-9. A total of 763 (365 girls, 398 boys) Finnish school students (11- to 12-year old) were followed across three years.…

This goal of this study was to examine the benefits of a campus-wide initiative to build first-year students' strengths awareness. The results of a survey of the first-year class (n?=?1,421) suggest a positive and significant relationship between students' strengths awareness and their belief that the strengths initiatives on campus positively…

A robust body of research has identified associations between positive teacher-child relationships--characterized by high levels of closeness and low levels of conflict--and children's academic achievement in elementary school (e.g. Roorda, 2012). Additional studies find that high-quality teacher-child relationships may promote academic resilience…