Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested…

Working Memory (WM) has a central role in learning. It is suggested to be malleable and is considered necessary for several aspects of mathematical functioning. This study investigated whether work with an interactive computerised working memory training programme at school could affect the mathematical performance of young children. Fifty-seven…