Tree diagram of possibilities: analysis of its construction by blind students

Abstract

The objective of this paper was to discuss the construction of the tree diagram of possibilities by three blind students from a high school in Brazil. This activity was part of the teaching sequence “Jefferson’s Random Walks,” which deals with probabilistic basic concepts. In the diagram, the combinations of the visits of Jefferson to five friends (placed on a 3D 5x5 board), depending on four coin tosses, were presented. Two plastic trays were used (representing the coin), foam cards of two different textures (representing each face), and toys to represent the visited friend. Students identified just four out of the six visiting paths at the board’s center. The researcher helped by identifying the missing paths, and the students registered all 16 possible paths. The importance of this study is to contribute to discussions about adaptation of materials and teaching methods for probabilistic contexts for blind students.