Realistic animations are more compelling and more effective for teaching. The best time to teach a concept or definition is when the student asks about it. But students must be able to find answers quickly and easily. The Glossary is context-sensitive, often citing the example under discussion at that point in the lesson. The glossary and index are linked together, so it is easy to find not just a definition, but also the point in the course that first discussed the concept.
Statistics is about understanding the world through data.
ActivStats videos take the student into the world to show applications of statistics. Students apply their newly acquired skills and understanding to real data. This reinforces learning because students use newly learned concepts and methods while they are fresh.