Stochastic understanding of probability distribution undergirds development of conceptual connections between probability and statistics and supports development of a principled understanding of statistical inference. This study investigated the impact of an instructional course intervention designed to support development of stochastic…

The study examining the validity of statistical conclusions of 49 early intervention studies found that 4 percent had adequate power to detect medium intervention effects and 18 percent to detect large intervention effects. Low statistical conclusion validity has practical consequences in program evaluation and cost-effectiveness determinations.…