Background: Although there is an established body of evidence attesting to the dose-effect relationship in psychotherapy with non-disabled adults, the issue as to whether such a relationship exists for persons with intellectual disabilities has not been previously examined. Dose-effect essentially concerns the amount of psychotherapy required to…

A method is outlined for evaluating the reliability and criterion validity of weighted scales based on sets of unidimensional measures. The approach is developed within the framework of latent variable modeling methodology and is useful for point and interval estimation of these measurement quality coefficients in counseling and education…

Confidence intervals are widely accepted as a preferred way to present study results. They encompass significance tests and provide an estimate of the magnitude of the effect. However, comparisons of correlations still rely heavily on significance testing. The persistence of this practice is caused primarily by the lack of simple yet accurate…

Standardized effect sizes and confidence intervals thereof are extremely useful devices for comparing results across different studies using scales with incommensurable units. However, exact confidence intervals for standardized effect sizes can usually be obtained only via iterative estimation procedures. The present article summarizes several…

Purchase probability as a function of interpurchase time was examined through comparison of findings from laboratory experiments on reinforcement schedules and from marketing investigations of consumers' interpurchase time. Panel data, based on a sample of 80 consumers who purchased nine supermarket food products during 16 weeks, were used. For…

Mediators are variables that explain the association between an independent variable and a dependent variable. Structural equation modeling (SEM) is widely used to test models with mediating effects. This article illustrates how to construct confidence intervals (CIs) of the mediating effects for a variety of models in SEM. Specifically, mediating…

Context: Physician supply is anticipated to fall short of national requirements over the next 20 years. Rural areas are likely to lose relatively more physicians. Policy makers must know how to anticipate what changes in distribution are likely to happen to better target policies. Purpose: To determine whether there was a significant flow of…

A number of methods are available in the literature to measure confidence intervals. Here, confidence intervals for estimating the population mean of a skewed distribution are considered. This note proposes two alternative confidence intervals, namely, Median t and Mad t, which are simple adjustments to the Student's t confidence interval. In…

In this study, the authors examined whether individuals with disabilities report higher levels of trauma symptoms than their nondisabled counterparts. Based on trauma theory and prior research regarding the incidence rate of posttraumatic stress disorder, the authors hypothesized that individuals with disabilities would report higher levels of…

The purpose of this study was to analyze the use of a course management system in relation to faculty characteristics and instructional environments at a rural community college in California. The use of the course management system, Blackboard, was the technology studied. This study used a nonexperimental quantitative ex post facto research…

Mammography screening rates among Chinese American women have been reported to be low. This study examines whether and how culture views and language ability influence mammography adherence in this mostly immigrant population. Asymptomatic Chinese American women (n = 466) aged 50 and older, recruited from the Washington, D.C. area, completed a…

Some probabilistic illustrations of the reliability coefficient are provided to assist in interpretation of this measure. All explanations are derived under the assumption that the joint distribution of examinee scores from two parallel tests is well approximated by a bivariate normal distribution.

Four possible situations in trend analyses in the analysis of variance are discussed: unequal sample sizes with unequal intervals, unequal sample sizes with equal intervals, equal sample sizes with unequal intervals, and equal sample sizes with equal intervals. (Author/JKS)

This study of the nature of the representations underlying children's knowledge of the pattern of daily activities tested the plausibility of three models that have been proposed to explain adults' representations of temporal patterns. The models could also account for previous demonstrations of young children's knowledge of the temporal order of…

Objective: To determine the empirical evidence for deficits in working memory (WM) processes in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Method: Exploratory meta-analytic procedures were used to investigate whether children with ADHD exhibit WM impairments. Twenty-six empirical research studies published from…