Pedagogical content knowledge is knowledge of effective strategies, representations, models, and examples for presenting mathematical content (Shulman, 1987). According to Steinbring (1991), successful learning of probability is dependent on the representations and activities teachers use. For example, he recommended that teachers use “task systems,” a well-
connected series of tasks, to develop probability concepts. Echoing Steinbring’s comments, Kvatinsky and Even (2002) identified various representations and models for probability teaching (e.g., tree diagrams, Venn diagrams, and tables) and advocated that teachers know when each representation or model is appropriate and how they are connected. Kvatinsky and Even also asserted that teachers need a basic repertoire of examples to illustrate probabilistic concepts,
properties, and theorems. Such a repertoire should utilize inter alia ideas connected to set theory and combinatorics. Finally, Steinbring and Kvatinsky and Even strongly advocated teachers’ use of both the classical and the frequentist approach. In fact, Stein-bring recommended the simultaneous use of both approaches in teaching probability concepts.