We address the very basic notions of statistics, which are in fact popular concepts, because they are required to be understood by any user of standard statistical packages (STATA, R, SPSS, SAS, PSPP). Similarly, these issues are extensively tailored to specific users in all methodological textbook and introductions to basic statistics and social science methodology.

The main added value of this supplement is that it outlines the essential concept in a very brief way. There are less than 30 pages of the core text, accompanied with extensive examples. This can be dealt within few hours, especially when it is a refreshment of some past statistical or methodological courses.