Effect sizes are important because they are an accessible way to indicate the practical importance of observed associations or differences. Standardized mean difference (SMD) effect sizes, such as Cohen's d, are widely used in education and the social sciences -- in part because they are relatively easy to calculate. However, SMD effect sizes…

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…

This design case discusses the complex collaborative design reasoning processes involved in developing an online interactive learning tool for learners of all ages to explore and understand the role of flagellate plants in our society. The learning tool consists of a main website (the "Voyager") and an interactive, dynamic map of the…

Since the publishing of Nolan and Temple Lang's "Computing in the Statistics Curriculum" in 2010, the American Statistical Association issued new recommendations in the revised GAISE college report. To reflect modern practice and technologies, they emphasize giving students experience with multivariable thinking. Students develop…

Describes two QuickBASIC programs that provide students direct experience with interpreting correlation scatter-plots. Maintains that the programs can be used in classroom exercises to highlight factors that influence the size of a Pearson correlation coefficient. (CFR)

Describes a QuickBASIC program for demonstrating the differences between main effects and interactions in factorial designs. The program can be used in conjunction with a traditional lecture to improve student understanding and develop skills in recognizing main effects and interactions from graphic displays. (CFR)