Conventional methods for mediation analysis generate biased results when the mediator--outcome relationship depends on the treatment condition. This article shows how the ratio-of-mediator-probability weighting (RMPW) method can be used to decompose total effects into natural direct and indirect effects in the presence of treatment-by-mediator…

When nonrandom treatments occur across sites, within-site matching (WM) is often desirable. This approach, however, can significantly reduce treatment group sample size and exclude substantively important subgroups. To limit these drawbacks, we extend a matching approach developed by Stuart and Rubin to a multisite study. We demonstrate the…

The number of increases a particular stock makes over a fixed period follows a Poisson distribution. This article discusses using this easily-found data as an opportunity to let students become involved in the data collection and analysis process.

The purpose of the present study was to extend past work with the Angoff method for setting standards by examining judgments at the judge level rather than the panel level. The focus was on investigating the relationship between observed Angoff standard setting judgments and empirical conditional probabilities. This relationship has been used as a…

Purpose: In this study, the authors assessed the effects of phonotactic probability and neighborhood density on word-learning configuration by preschoolers with specific language impairment (SLI) and typical language development (TD). Method: One hundred thirty-one children participated: 48 with SLI, 44 with TD matched on age and gender, and 39…

The dice game Farkle provides an excellent basis for four activities that reinforce probability and expected value concepts for students in an introductory statistics class. These concepts appear in the increasingly popular AP statistics course (Peck 2011) and are used in analyzing ethical issues from insurance and gambling (COMAP 2009; Woodward…

Understanding the roles of random selection and random assignment in experimental design is a central learning objective in most introductory statistics courses. This article describes an activity, appropriate for a high school or introductory statistics course, designed to teach the concepts, values and pitfalls of random selection and assignment…

The key purpose of educational welfare officers in England is to support students and parents to maximise educational opportunities for young people. However more is known about their role in relation to school attendance than in relation to pupils' educational outcomes. Using the Longitudinal Survey of Young People in England (LSYPE), this paper…

Learning the structure of event sequences is a ubiquitous problem in cognition and particularly in language. One possible solution is to learn a probabilistic generative model of sequences that allows making predictions about upcoming events. Though appealing from a neurobiological standpoint, this approach is typically not pursued in…

Because new learning technologies are enabling students to build and explore probability models, we believe that there is a need to determine the big enduring ideas that underpin probabilistic thinking and modeling. By uncovering the elements of the thinking modes of expert users of probability models we aim to provide a base for the setting of…

Objective: To obtain information on varicella prematriculation requirements in US colleges for undergraduate students during the 2014-2015 academic year. Participants: Health care professionals and member schools of the American College Health Association (ACHA). Methods: An electronic survey was sent to ACHA members regarding school…

Leveraging a sample of more than 198,000 adult entrepreneurs, both currently involved in the startup of a business or formerly involved in business creation, this study investigates the perceptual, societal impression, economic, and demographic variables that are predictive with an individual's decision to engage in entrepreneurial activity.…

Northwest Evaluation Association™ (NWEA™) is committed to providing partners with useful tools to help make inferences from Measures of Academic Progress® (MAP®) interim assessment scores. One important tool is the concordance table between MAP and state summative assessments. Concordance tables have been used for decades to relate scores on…

Using the 2012 PIAAC data, our analysis confirms that there are significantly higher earnings and employment returns to "both" increasing levels of formally recognised education, and to increasing levels of numeracy, literacy and information and communication technologies (ICT) skills proficiencies controlling for the level of education.…

The objective of this thesis is two-fold: (1) to investigate the degree distribution property of community-based social networks (CSNs) and (2) to provide solutions to a pertinent problem, the Key Player Problem. In the first part of this thesis, we consider a growing community-based network in which the ability of nodes competing for links to new…