K-means cluster analysis is known for its tendency to produce spherical and equally sized clusters. To assess the magnitude of these effects, a simulation study was conducted, in which populations were created with varying departures from sphericity and group sizes. An analysis of the recovery of clusters in the samples taken from these…

There is no shortage of recommendations regarding the appropriate sample size to use when conducting a factor analysis. Suggested minimums for sample size include from 3 to 20 times the number of variables and absolute ranges from 100 to over 1,000. For the most part, there is little empirical evidence to support these recommendations. This…

The hierarchical latent regression model (HLRM) is a flexible framework for estimating group-level proficiency while taking into account the complex sample designs often found in large-scale educational surveys. A complex assessment design in which information is collected at different levels (such as student, school, and district), the model also…

In this article, the author describes a simulation of a coevolutionary "arms race" and introduce a way of teaching it that lets students use the theory of natural selection to explain the outcomes of the simulation. The simulation uses the numerical cards from an UNO[R] playing card deck to represent the speeds of individuals in populations of…

A commonly attempted approach to modifying attitudes regarding people with disabilities is to place people without disabilities in situations that are designed for them to experience what it is like to have a disability. This approach, called disability simulation, continues despite criticisms including a reported lack of effectiveness data and…

As part of its efforts to ensure school safety, the government of New South Wales, Australia, has developed simulation exercises to better prepare principals to manage serious incidents, in collaboration with police. This article describes two initiatives implemented across NSW. The exercises provide principals in both secondary and primary…

A widely used approach for categorizing the level of differential item functioning (DIF) in dichotomous items is the scheme proposed by Educational Testing Service (ETS) based on a transformation of the Mantel-Haeszel common odds ratio. In this article two classification schemes for DIF in polytomous items (referred to as the P1 and P2 schemes)…

People tend to perceive ongoing continuous activity as series of discrete events. This partitioning of continuous activity may occur, in part, because events correspond to dynamic patterns that have recurred across different contexts. Recurring patterns may lead to reliable sequential dependencies in observers' experiences, which then can be used…

Psychologists are applying growth mixture models at an increasing rate. This article argues that most of these applications are unlikely to reproduce the underlying taxonic structure of the population. At a more fundamental level, in many cases there is probably no taxonic structure to be found. Latent growth classes then categorically approximate…

In this paper we describe our research using a multi-user virtual environment, "Quest Atlantis," to embed fourth grade students in an aquatic habitat simulation. Specifically targeted towards engaging students in a rich inquiry investigation, we layered a socio-scientific narrative and an interactive rule set into a multi-user virtual environment…

We explore in this study how infants may derive phonetic categories from adult input that are highly variable. Neural networks in the form of self-organizing maps (SOMs; Kohonen, 1989, 1995) were used to simulate unsupervised learning of Mandarin tones. In Simulation 1, we trained the SOMs with syllable-sized continuous F[subscript 0] contours,…

Public health relies on well trained nurses and clinical experience is an important component of that training. However, clinical experience training for student nurses also has significant challenges, as it can place patients at risk. Also it is difficult to schedule/predict patient conditions and procedures. Human patient simulation (HPS) can…

This article proposes a VHDL language course that establishes a strong correlation between the language statements and their use in circuit synthesis. Two course modules are described: a basic module that contains the essential concepts of the language, sufficient for students to describe medium complexity circuits, followed by a second module…

This work describes a new "Moodle" module developed to give support to the practical content of a basic computer organization course. This module goes beyond the mere hosting of resources and assignments. It makes use of an automatic checking and verification engine that works on the VHDL designs submitted by the students. The module automatically…

An Educational Testing Service (ETS) procedure was evaluated, which is based on item response theory and estimates true scores on tests not taken. The reading, vocabulary, and mathematics tests of high school seniors from the National Longitudinal Study (NLS) of 1972 and the High School and Beyond (HSB) seniors of 1980 and 1982 were found to share…