Pages in the Lesson Book often have asterisks. Clicking on an asterisk opens a window with optional additional material. Often this material is an additional example or background material. Some asterisk additions are quoted from Basic Practice of Statistics by David Moore, others quote from Elementary Statistics by Mario Triola, still others are additional comments by the author of ActivStats.

Each Lesson in ActivStats offers a footnote at the end of the introductory paragraph providing references to the sections of popular textbooks that correspond to that Lesson. ActivStats can be used with any text, but these references help to anchor it in common teaching practice.