Where's your evidence? Challenging young students' equiprobability bias through argumentation

Students come to formal schooling with prior probabilistic conceptions developed through informal experiential events. One such concept is that of chance outcomes being inherently equiprobable, even when not the case. In the design-based research described here, a class of 3rd Grade students was posed an inquiry problem embedded with non-equiprobable outcomes: What is the best addition bingo card? Argumentation was employed as a pedagogic approach to challenging students' equiprobable beliefs, with students supported to develop an evidence-based argument in response. Students initially experienced conflict with the realisation of unequal frequencies, then developed representations to act as theoretical evidence. A shift from conceptualizing equiprobable outcomes towards responses reflecting theoretical distribution was observed. This exploratory research suggests potential for an evidentiary focus to challenge probabilistic conceptions.