In this paper, we explore the impact of two types of instruc- tional interventions, worked examples and problem solving, at two levels of granularity: problems and steps. This study drew on an existing Intelligent Tutoring System (ITS) for Probabil- ity called Pyrenees and involved 266 students who were ran- domly assigned to five conditions. All students experienced the same procedure, studied the same training problems in the same order, and used the same ITS. The conditions differed only in how the training problems were presented. Our re- sults showthat when the domain content and required steps are strictly equivalent, different granularities of pedagogical deci- sions can significantly impact students’ time on task. More specifically, the fine-grained step level decisions can have a stronger pedagogical impact than the problem-level ones. Keywords: