Probabilistic Content Knowledge
In a recent review Stohl (2005) examined four studies that have investigated teachers’ beliefs and content knowledge in probability. Working in New Zealand, Begg and Edwards (1999) found that 22 practicing and 12 preservice elementary teachers had a weak knowledge of probability with only about two thirds understanding equally likely events and even
fewer understanding independence. Carnell (1997) investigated 13 preservice middle school teachers’ understanding of conditional probability. He concluded that each of the teachers showed evidence of holding one or more misconceptions described earlier in this chapter: fallacy of the time axis, finding the conditioning event, and confusing conditionality with causality (Falk, 1988). In a broader study in Australia, Watson (2001) developed a profile instrument to gather information about elementary (n = 15) and secondary (n = 28) teachers’ content and pedagogical knowledge in stochastics. She reported that secondary teachers were significantly more confident than elementary teachers in their ability to teach equally likely outcomes, basic probability measurement, and sampling. In addition, she observed that the majority of teachers had particular difficulty in interpreting 7:2 correctly as “odds” and were unable to transition between part-part odds (7:2) and part-whole probability (7/9 or 2/9). In a related area, Stohl (2005) also noted that mathematics
teachers have a deterministic mindset in that they experience difficulty in moving mathematically from situations that deal with certainty to situations that deal with uncertainty and nondeterministic reasoning. This finding is corroborated in research on secondary teachers by Nicholson and Darnton (2003) and with elementary teachers by Pereira-Mendoza (2002).