Interactive computer-based simulations have been applied in several contexts to teach statistical concepts in university level courses. In this report, the use of interactive simulations as part of summative assessment in a statistics course is described. Students accessed the simulations via the web and completed questions relating to the simulations. Importantly, the questions could only be answered by combining declarative knowledge of statistics with the experiences resulting from actively engaging with the simulation. In this way, the assessment approach was able to assess functional knowledge related to procedural concepts and skills in application. The answers were submitted on-line and students received immediate feedback on the grade obtained. The interactive assessment tool was used by a large proportion of the students in the course. Feedback given by the students is discussed to give an indication of the benefits and limitations to its use. (Contains 3 figures.)