Confidence intervals are difficult to teach, in part because most students appear to believe they understand how to interpret them intuitively. They rarely do. To help them abandon their misconception and achieve understanding, we have developed a simulation tool that encourages experimentation with multiple confidence intervals derived from the…

A colleague was moving, and someone on the professional moving crew, upon hearing she was a mathematician, asked what happens when you repeatedly transfer water back and forth between two classes using a straw. The question is simple to solve if you alternate which glass you transfer from and to, but if more general patters are allowed, some…

The currently available meta-analytic methods for correlations have restrictive assumptions. The fixed-effects methods assume equal population correlations and exhibit poor performance under correlation heterogeneity. The random-effects methods do not assume correlation homogeneity but are based on an equally unrealistic assumption that the…

Evidence of group matching frequently takes the form of a nonsignificant test of statistical difference. Theoretical hypotheses of no difference are also tested in this way. These practices are flawed in that null hypothesis statistical testing provides evidence against the null hypothesis and failing to reject H[subscript 0] is not evidence…

This article offers suggestions for teaching confidence intervals, a fundamental statistical tool often misinterpreted by beginning students. A historical perspective presenting the interpretation given by their inventor is supported with examples and the use of technology. A method for determining confidence intervals for the seldom-discussed…

Stimuli uncorrelated with reinforcement have been shown to enhance response rates and resistance to disruption; however, the effects of different rates of stimulus presentations have not been assessed. In two experiments, we assessed the effects of adding different rates of response-dependent brief stimuli uncorrelated with primary reinforcement…

This study examined the influence of sex, social dominance, and context on motion-tracked head movements during dyadic conversations. Windowed cross-correlation analyses found high peak correlation between conversants' head movements over short ([approximately equal to]2-s) intervals and a high degree of nonstationarity. Nonstationarity in head…

The GluA1 AMPA receptor subunit is a key mediator of hippocampal synaptic plasticity and is especially important for a rapidly-induced, short-lasting form of potentiation. GluA1 gene deletion impairs hippocampus-dependent, spatial working memory, but spares hippocampus-dependent spatial reference memory. These findings may reflect the necessity of…

Background: Emotion regulation (ER) has been conceptualized as an ongoing process of the individual's emotion patterns in relation to moment-to-moment contextual demands. In contrast to traditional approaches of descriptively quantizing ER, we employed a dynamic approach to ER by examining key transitions in infants of clinically depressed and…

Confidence intervals (CIs) for parameters are usually constructed based on the estimated standard errors. These are known as Wald CIs. This article argues that likelihood-based CIs (CIs based on likelihood ratio statistics) are often preferred to Wald CIs. It shows how the likelihood-based CIs and the Wald CIs for many statistics and psychometric…

Consonance and dissonance are subjective perceptions that are reactions of the human ear to whether or not musical intervals sound "pleasing." The physical causes of consonance and dissonance are not as well understood as other subjective properties of sound perceived by the ear such as pitch, loudness, and quality (timbre). What follows is an…

This article describes SIMREL, a software program designed for the simulation of alpha coefficients and the estimation of its confidence intervals. SIMREL runs on two alternatives. In the first one, if SIMREL is run for a single data file, it performs descriptive statistics, principal components analysis, and variance analysis of the item scores…

One current conceptualization of attention subdivides it into functions of alerting, orienting, and executive control. Alerting describes the function of tonically maintaining the alert state and phasically responding to a warning signal. Automatic and voluntary orienting are involved in the selection of information among multiple sensory inputs.…

The authors examined, by direct observation and 1 hr interval self-reporting, teacher time use in 4 types of special education programs (adaptive behavior units, content mastery, coteaching, resource room). Over 7,000 pieces of data were collected across an academic year from 31 teachers in 24 schools within 9 districts in the Southwestern United…

Objective: To help professionals identify factors that place families at risk for future child maltreatment, to facilitate necessary services and to potentially help prevent abuse and neglect. Method: The data are from a prospective, longitudinal study of 332 low-income families recruited from urban pediatric primary care clinics, followed for…