Collected Introductory Multivariate pages
Articles on the basic principles and practice of Multivariate Statistics - suitable for new-comers and beginners.
Core functions in R that you need to memorise.
Core building blocks in statistics that you need to memorize.
Sampling error of the mean:
var(df$yourVar)/sqrt(length(df$yourVar))
Critical statistics are the ratio of an effect size compared to a sampling error. For instance, t = ES / SE