Contains tools useful for data screening, testing moderation (Cohen et. al. 2003)<doi:10.4324/9780203774441>, mediation (MacKinnon et. al. 2002)<doi:10.1037/1082-989x.7.1.83> and estimating power (Murphy & Myors 2014)<ISBN:9781315773155>.
copied from cf-staging / r-quantpsyc