When well-implemented, mediation analyses play a critical role in probing theories of action because their results help lay the ground work for the critical development of a treatment and the iterative advancement of theories that are foundational to a discipline. Despite strong interest in designs that incorporate mediation, few studies have…

It is widely believed that regression models for binary responses are problematic if we want to compare estimated coefficients from models for different groups or with different explanatory variables. This concern has two forms. The first arises if the binary model is treated as an estimate of a model for an unobserved continuous response and the…

Educational inequalities are one of the most critical issues facing contemporary societies. While there is a substantial body of quantitative literature tracking inequalities in education based on students' characteristics, an emerging literature is applying the concept of intersectionality to acknowledge the multiple, overlapping impact of these…

In this article, alternative randomized response models are proposed, which make use of sum of quantitative scores generated from two decks of cards being used in a survey. The proposed methods are compared to the Odumade and Singh and Singh and Grewal models through a simulation study. It is shown that the modified methods can be used more…

As a result of the COVID-19 pandemic, at-home testing has become a popular delivery mode in many testing programs. When programs offer at-home testing to expand their service, the score comparability between test takers testing remotely and those testing in a test center is critical. This article summarizes statistical procedures that could be…

The ability to collaborate with culturally diverse groups is essential, not only to further scientific knowledge but also to solve complex global problems. However, not all students have opportunities to develop intercultural competencies through study abroad programs, due to various issues such as cost, rigid curriculum, and unrelated field of…

This article develops new closed-form variance expressions for power analyses for commonly used difference-in-differences (DID) and comparative interrupted time series (CITS) panel data estimators. The main contribution is to incorporate variation in treatment timing into the analysis. The power formulas also account for other key design features…

Social scientists are often interested in estimating the marginal effects of a time-varying treatment on an end-of-study continuous outcome. With observational data, estimating these effects is complicated by the presence of time-varying confounders affected by prior treatments, which may lead to bias in conventional regression and matching…

The present guide provides a practical guide to conducting latent profile analysis (LPA) in the Mplus software system. This guide is intended for researchers familiar with some latent variable modeling but not LPA specifically. A general procedure for conducting LPA is provided in six steps: (a) data inspection, (b) iterative evaluation of models,…

The Michelson interferometer is one of the key experiments in modern physics when it comes to the topic of interference (Box 1). Experiments using interferometry have a high historic relevance as well as uses in current areas of research (quantum erasers, gravitational wave detection) and are used in higher education. Because of the high cost of…

We describe a series of three experiments in which students develop a model system for measuring the LC50 of household substances, using grass seed as the model organism. Students use statistical methods to compare two samples (using chi-square and Student's "t"-tests), conduct a two-level multifactor experiment to look at multiple…

The year 2022 is the 20th anniversary of Joseph Schafer and John Graham's paper titled "Missing data: Our view of the state of the art," currently the most highly cited paper in the history of "Psychological Methods." Much has changed since 2002, as missing data methodologies have continually evolved and improved; the range of…

This paper presents the operation of the educational software, Real Estate Data Analyzer, to teachers and future teachers. It is a specific software that allows students carry out complete statistical analysis projects on the characteristics of the buildings that surround them.

This article offers some less-than-rigorous explanations for the notion of degrees of freedom, and for the particular formulae to be used when computing those values.

The article presents some notes on normalization and illustrates these procedures using graphing functions in R. Using real data, the paper also presents an R package and online Shiny app that efficiently transforms variables in large datasets.