This paper concerns the didactical knowledge of two mathematics teachers while teaching bivariate data and their relationships, when covering the statistics subject of the discipline of Mathematics A, at the secondary level, in Portugal. In particular, we analyze the dimensions of the teaching knowledge and knowledge of students and learning of the teachers' didactical knowledge; we also address how these dimensions relate to each other and to the others dimensions of the teachers' didactical knowledge, mainly through the observation of the teaching practice of both teachers in their 10th grade classes. The results showed that in several aspects, teachers seem not consider how complex it is for students to reason about bivariate data. There are fundamental notions and representations emerging from the situations worked in the classes that are not explored with the appropriate depth.
Didactical Knowledge; Statistics; Bivariate Data; Secondary School
