It is well known that students of inferential statistics find the hypothetical, probabilistic reasoning used in hypothesis tests difficult to understand. Consequently, they will also have difficulties in understanding "p"-values. It is not unusual for these students to hold misconceptions about "p"-values that are difficult to…

In 1881, Donald MacAlister posed a problem in the "Educational Times" that remains relevant today. The problem centers on the statistical evidence for the effectiveness of a treatment based on a comparison between two proportions. A brief historical sketch is followed by a discussion of two default Bayesian solutions, one based on a…

Student employment subsidies are one of the largest types of employment subsidies and one of the oldest forms of student aid. The Federal Work-Study program (FWS) is the largest student employment subsidy program; since 1964, it has provided about $1 billion per year to cover 75 percent of wages for student employees, who typically work on campus…

There are many well-known data sets that can be used to illustrate Simpson's Paradox. The Stand Your Ground data presented here shows Simpson's Paradox. In these data, race plays the key role--and not in the way that some students expect.

Multilevel models are often used to evaluate hypotheses about relations among constructs when data are nested within clusters (Raudenbush & Bryk, 2002), although alternative approaches are available when analyzing nested data (Binder & Roberts, 2003; Sterba, 2009). The overarching goal of this article is to suggest when it is appropriate…

Being able to characterize the size of raindrops is useful in a number of fields including meteorology, hydrology, agriculture and telecommunications. Associated with this article are data sets containing surface (i.e. ground-level) measurements of raindrop size from two different instruments and two different geographical locations. Students may…

This longitudinal study of 78 Canadian English-speaking students examined the applicability of the stability, cumulative, and compensatory models in reading comprehension development. Archival government-mandated assessments of reading comprehension at Grades 3, 6, and 10, and the Canadian Test of Basic Skills measure of reading comprehension…

Using detailed administrative data from Virginia, this paper examines how and why the community college pathway to a baccalaureate influences students' degree attainment and short-term labor market performance. We find that the community college pathway sharply reduces the likelihood of earning a bachelor's degree but does not have a significant…

Many adults who need an understanding of statistical concepts have limited mathematical skills. They need a teaching approach that includes as little mathematical context as possible. Iterative participatory qualitative research (action research) was used to develop a statistical literacy course for adult learners informed by teaching in…

Although uniquely positioned to provide insight into the nature and dynamics of terrorism, overall the field of criminology has seen few empirically focused analyses of this form of political violence. This article seeks to add to the understanding of terror through an exploration of how general levels of violence within a given society influence…

In this paper, we exploit a rich longitudinal data set to explore the forces that, during high school, shape the development of aspirations to attend university and achieve academic success. We then investigate how these aspirations, along with grades and other variables, impact educational outcomes such as going to university and graduating. It…

Because of the Flynn effect, IQ scores rise as a test norm ages but drop on the introduction of a newly revised test norm. The purpose of the current study was to determine the impact of the Flynn effect on learning disability (LD) diagnoses, the most prevalent special education diagnosis in the United States. Using a longitudinal sample of 875…

The group's absence norm, a construct from the applied psychology literature, was used to examine session absences in personal growth groups. Rather than examining the absence norm statically, we modeled it dynamically as a time-varying covariate (Tasca et al., 2010). We also examined moderation by modeling the interaction of the absence norm and…

Although it is clear that increasing depression severity is associated with more risk for suicidality, less is known about at what levels of depression severity the risk for different suicide symptoms increases. We used item response theory to estimate the likelihood of endorsing suicide symptoms across levels of depression severity in an…

A new test index is defined as the probability of obtaining two randomly selected test scores (PDTS) as statistically different. After giving a concept definition of the test index, two simulation studies are presented. The first analyzes the influence of the distribution of test scores, test reliability, and sample size on PDTS within classical…