This article is concerned with the question of whether the missing data mechanism routinely referred to as missing completely at random (MCAR) is statistically examinable via a test for lack of distributional differences between groups with observed and missing data, and related consequences. A discussion is initially provided, from a formal logic…

We describe an easy-to-employ, hands-on demonstration using playing cards to illustrate the central limit theorem. This activity allows students to see how a collection of sample means drawn from a nonnormally distributed population will be normally distributed. Students who took part in the demonstration reported it to be helpful in understanding…

During the 1990s, the use of meta-analytic methods in educational research has been widespread, and few aspects of education have escaped the meta-analytic revolution. The acceptance has not been complete, however, and several threats to validity remain. Prominent among these are the "normality" problem and the "independence"…