The 7 Dimensions of Applied Behavior Analysis were first defined by Baer, Wolf, & Risley in 1968, alongside the founding of what was intended (and has become) ABA's flagship journal, the Journal of Applied Behavior Analysis.
Behavior analysts - including RBTs - must practice within their scope. While having the 7 dimensions memorized is not a requirement for the RBT exam, it's helpful to understand what behavior analysis is so that you can ensure you stay safely within the bounds of your scope of practice.