Structural equation modeling (SEM) is a powerful and flexible analytic tool to model latent constructs and their relations with observed variables and other constructs. SEM applications offer advantages over classical models in dealing with statistical assumptions and in adjusting for measurement error. So far, however, SEM has not been fully used…

The hierarchical network model (HNM) is a framework introduced by Sweet, Thomas, and Junker for modeling interventions and other covariate effects on ensembles of social networks, such as what would be found in randomized controlled trials in education research. In this article, we develop calculations for the power to detect an intervention…

We discuss a teaching experiment that explored two pre-service secondary teachers' meanings for the unit circle. Our analyses suggest that the participants' initial unit circle meanings predominantly consisted of calculational strategies for relating a given circle to what they called "the unit circle." These strategies did not entail…

Two questions about certainty in mathematics are asked. First, is mathematical knowledge known with certainty? Second, why is the belief in the certainty of mathematical knowledge so widespread and where does it come from? This question is little addressed in the literature. In explaining the reasons for these beliefs, both cultural-historical and…

This study was designed to investigate children's abilities to count and make quantitative comparisons. In addition, this study utilized reasoning questions (i.e., how did you know?). Thirty-four preschoolers, mean age 4.5 years old, participated in the study. According to the results, 89% of the children (n = 30) were able to do rote counting and…

In this essay, Amy Voss Farris and Pratim Sengupta argue that a democratic approach to children's computing education in a science class must focus on the "aesthetics" of children's experience. In "Democracy and Education," Dewey links "democracy" with a distinctive understanding of "experience." For Dewey,…

Concentration of solutions problems are among the most important and at the same time one of the most challenging topics in chemistry. The aim of this study was to determine the sources of the difficulty that students often face when performing calculations related to concentration. The study involved 153 tertiary college students (food science,…

Unavoidable sample size issues beset psychological research that involves scarce populations or costly laboratory procedures. When incorporating longitudinal designs these samples are further reduced by traditional modeling techniques, which perform listwise deletion for any instance of missing data. Moreover, these techniques are limited in their…

BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

The second law of thermodynamics has various formulations. There is the "Clausius formulation," which can be stated in a very intuitive way: "No process is possible whose sole result is the transfer of heat from a cooler to a hotter body." There is also the "Kelvin-Plank principle," which states that "no cyclic…

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is widely used in diagnosis and research to determine specific mRNA expressions in cells. As RT-qPCR applications increase, it is necessary to provide undergraduates hands-on experience of this modern technique. Here, we report a 3-week laboratory exercise using RT-qPCR to…

In this article we develop a methodology for the joint value added analysis of multiple outcomes that takes into account the inherent correlation between them. This is especially crucial in the analysis of higher education institutions. We use a unique Colombian database on universities, which contains scores in five domains tested in a…

It is important for students to make informed decisions about computation. This article highlights this importance and develops a framework which may assist teachers to help students to make effective computational choices.

British mathematics educator Tony Cotton suggests that teachers use math instruction to help students--who live in an internationally connected world--ponder international events and the global implications of policies in depth. He describes two math-based activities toward that end. First, teachers might guide learners in examining data connected…

Meta-analyses are typically used to estimate the overall/mean of an outcome of interest. However, inference about between-study variability, which is typically modelled using a between-study variance parameter, is usually an additional aim. The DerSimonian and Laird method, currently widely used by default to estimate the between-study variance,…