It is fully documented in the accompanying stats.html. This is supported by a wallpaper file (swirlies.gif) and style sheet (eustyle.css).
The library can be used in a number of ways but there were two uppermost in my mind when I created it:
In a folder entitled "Examples" are several worked examples which show how the library routines can be used, both directly and in conjunction with some Euphoria programming. In fact most examples turn out to be more like the second type described above. Each example is in the form of a console-based program (so that it can be run on any platform), which contains annotations both inside the code and in the output. Most of the example come directly from one of the best ever Statistics textbooks:
"Statistical Principles in Experimental Design" by B. J. Winer.
The version I have used in preparing these examples, was published in 1977 by McGraw-Hill Kogakusha. There are earlier editions and certainly later ones, written in collaboration with other authors.
Each example from the book is titled by the Table in the book to which it refers. So Winer1.10.1.ex is based on Table 1.10-1, etc. Each example makes some use of a library file basics.e, designed to aid annotation.
It is not essential that you refer to the book to understand the examples, but if you are inspired to use the library further then I can certainly recommend the source.
All non-Winer examples include a source reference.