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…

The importance of numeracy for professional practice in nursing is increasingly recognized in the USA, UK and elsewhere, but there is no consensus on what is meant by numeracy for nursing, nor on how it should be taught, learned and assessed. Meanwhile, studies in various countries indicate a lack of proficiency in numeracy of some students and…

In one of the classic free-fall experiments, a small mass is attached to a strip of paper tape and both are allowed to fall through a spark timer, where sparks are generated at regular time intervals. Students analyze marks (dots) left on the tape by the timer, thereby generating distance-versus-time data, which they analyze to extract the…

This pilot study examined the development of complexity and fluency of second language (L2) spoken production among L2 learners who received extensive practice on grammatical chunks as constituent units of discourse. Twenty-two students enrolled in an elementary Japanese course at a U.S. university received classroom instruction on 40 grammatical…

The "co-familiality" criterion for an endophenotype has two requirements: (1) clinically unaffected relatives as a group should show both a shift in mean performance and an increase in variance compared with controls; (2) performance scores should be heritable. Performance on the antisaccade task is one of several candidate endophenotypes for…

This study examined the role of variability and change in children's strategy performance within the context of spelling. The spelling ability of 34 eight- to nine-year-olds was examined using an experimental spelling task comprising 45 items, which varied with regard to rime unit frequency. The spelling task incorporated a series of consistent,…

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.