The Northwestern University Initiative for Teaching Nanosciences (NUITNS) at nanohub.org Web site combines several tools for doing electronic structure calculations and analyzing and displaying the results into a coordinated package. In this article, we describe this package and show how it can be used as part of an upper-level quantum chemistry…

The present study investigated to what extent children with specific language impairment (SLI) differ in their early numeracy skills, when compared to normal language achieving (NLA) children. It was also explored which precursors were related to the early numeracy skills in both groups. Sixty-one children with SLI (6; 1 years) and 111 NLA…

Researchers commonly compare means and other statistics across groups with little concern for whether the measure possesses strong factorial invariance (i.e., equal factor loadings and intercepts/thresholds). When this assumption is violated, inaccurate inferences associated with statistical and practical significance can occur. This manuscript…

Course research projects that use easy-to-access real-world data and that generate findings with which undergraduate students can readily identify are hard to find. The authors describe a project that requires students to estimate the current female-male earnings gap for new college graduates. The project also enables students to see to what…

The relation between skill in simple addition and subtraction and more general math achievement in elementary school is well established but not understood. Both the intrinsic importance of skill in simple calculation for math and the influence of conceptual knowledge and cognitive factors (working memory, processing speed, oral language) on…

What does it look like to "understand" operations with fractions? The Common Core State Standards for Mathematics (CCSSM) uses the term "understand" when describing expectations for students' knowledge related to each of the fraction operations within grades 4 through 6 (CCSSI 2010). Furthermore, CCSSM elaborates that…

Many latent traits in the human sciences have a hierarchical structure. This study aimed to develop a new class of higher order item response theory models for hierarchical latent traits that are flexible in accommodating both dichotomous and polytomous items, to estimate both item and person parameters jointly, to allow users to specify…

Background: Individuals with intellectual and developmental disabilities (IDD) experience high rates of physical and mental health problems; yet their health care is often inadequate. Information about their characteristics and health services needs is critical for planning efficient and equitable services. A logical source of such information is…

Despite the widespread popularity of growth curve analysis, few studies have investigated robust growth curve models. In this article, the "t" distribution is applied to model heavy-tailed data and contaminated normal data with outliers for growth curve analysis. The derived robust growth curve models are estimated through Bayesian…

Statistics, econometrics, investment analysis, and data analysis classes often review the calculation of several types of averages, including the arithmetic mean, geometric mean, harmonic mean, and various weighted averages. This note shows how each of these can be computed using a basic regression framework. By recognizing when a regression model…

This paper uses an approximate average percent-correct methodology to compare the ranks that would be obtained for PISA 2006 countries if the rankings had been derived from items judged by each country to be of highest priority for inclusion. The results reported show a remarkable consistency in the country rank orderings across different sets of…

Most thermodynamic properties are either extensive (e.g., volume, energy, entropy, amount, etc.) or intensive (e.g., temperature, pressure, chemical potential, mole fraction, etc.). By the same token most of the mathematical relationships in thermodynamics can be written in extensive or intensive form. The basic laws of thermodynamics are usually…

The issues related to environmental sustainability can be overwhelming. It is difficult to imagine that actions of one person could make a difference. This article addresses that perception and illustrates the impact of one person, a family and consumer sciences educator, on the lives of others and on environmental resources. Making a difference…

The past two decades of attention to introductory physics education has emphasized enhanced development of conceptual understanding to accompany calculational ability. Given this, it is surprising that current texts continue to rely on the Bohr model to develop a flawed intuition, and introduce correct atomic physics on an ad hoc basis. For…

When grocery stores sell solutions of ammonia, they are labeled "ammonia"; however, when the same solution is purchased from chemical supply stores, they are labeled "ammonium hydroxide". The goal of this experiment is for students to determine which name is more appropriate. In this experiment, students use several different experimental methods…