This program generates maximum likelihood estimates of the parameters of a mixture of two normal distributions and tests the significance of the mixture hypothesis against that of a single normal distribution. (Author)

Methods to compare population means in the univariate case and population mean vectors in the multivariate case are presented in terms of hypotheses tested by various procedures. Tests relevant to each hypothesis are described and compared in terms of maximizing power while controlling Type I error rates over the widest variety of conditions. (SLD)

A theorem is developed to show that the Kruskal-Wallis test (W. Kruskal and W. Wallis, 1952) (KWt) can be used validly to test a hypothesis about location under much less restrictive conditions than required by the recently accepted, mathematically correct shift model. The specific null hypothesis for which the KWt can be used validly is…

The difference in statistical power between the original Bonferroni and five modified Bonferroni procedures that control the overall Type I error rate is examined in the context of a correlation matrix where multiple null hypotheses are tested. Power differences of less than 0.05 were typically observed for the modified Bonferroni procedures. (SLD)

Illustrates procedures for prediction analysis in 2 X 2 contingency tables through the analyses of solutions of six types of problems associated with the acquisition of fractions. Reviews and extends confidence interval procedures previously proposed for an index of predictive efficiency of implication hypotheses. Compares frequentist coverage…

Discusses problems in detecting nonlinear associations and investigates the use of two statistics for this purpose. Simulation results suggest that the Cramer-von Mises form of the test statistic is generally better than the Kolmogorov-Smirnov form. Discusses the power of this method. (SLD)

In this paper, the author reviews recently published videos that depict the roles played by myosin II in contraction of the cortical ring during cellularization and cytokinesis in early development (Royou et al., 2004), by spindle and astral microtubules in regulating the formation of cleavage furrows during the cleavage of primary spermatocytes…

Some game users have contended that students can be successful in games even if they "know little" about the rules and the underlying business theories driving them. Thus, if teams are uninvolved, it is possible that successful game play may not impart the learning typically found in experiential exercises nor that designed into games by their…

People often learn actions by watching others. The authors propose and test the hypothesis that perspective taking promotes encoding a hierarchical representation of an actor's goals and subgoals-a key process for observational learning. Observers segmented videos of an object assembly task into coarse and fine action units. They described what…

This paper will describe the relationships between research on learning and its application in assessment models and operational systems. These have been topics of research at the National Center for Research on Evaluation, Standards, and Student Testing (CRESST) for more than 20 years and form a significant part of the intellectual foundation of…

Differential activation levels of the two hemispheres due to hemispheric specialization for various linguistic processes might determine hand choice for co-speech gestures. To test this hypothesis, we compared hand choices for gesturing in 20 healthy right-handed participants during explanation of metaphorical vs. non-metaphorical meanings, on the…

This research tested the hypothesis that initial efforts at executive control temporarily undermine subsequent efforts at executive control. Four experiments revealed that controlling the focus of visual attention (Experiment 1), inhibiting predominant writing tendencies (Experiment 2), taking a working memory test (Experiment 3), or exaggerating…

This paper investigates the relationship between the phonological features of tone and tone perception in Thai. Specifically, it tests the hypothesis (proposed by Moren & Zsiga, 2006) that the principle perceptual cues to the five-way tonal contrast in Thai are high and low pitch targets aligned to moras. Results of four perception studies, one…

This research tested the response inhibition account of the hand-advantage found in the finger precuing task. According to this account, the advantage of preparing two fingers on one hand (represented in one hemisphere) as opposed to preparing two fingers on two hands (represented in two hemispheres) is due, in part, to a response inhibition…

The authors propose a framework for teacher preparation programs that aims to help prospective teachers learn how to teach from studying teaching. The framework is motivated by their interest in defining a set of competencies that provide a deliberate, systematic path to becoming an effective teacher over time. The framework is composed of four…