This paper is from Session 3A: Statistics instructors’ content knowledge

which comes under Topic 3: Education and development of staff who teach statistics

Analysis of teachers’ understanding of variation in the dot-boxplot context

Presenter

• Cláudia Borim da Silva (University of São Judas, Brazil)

Co-authors

• Irene Cazorla (State University of Santa Cruz, Brazil)
• Verônica Yumi Kataoka (State University of Santa Cruz, Brazil)

Abstract

This study examined how dotplots and boxplots helped 23 secondary school mathematics teachers engaged in didactic activity to develop reasoning about variation. Teachers described height and head circumference by using data arranged in a dotplot and in a dot-boxplot. Their reasoning about variation was explored further with these dotplots and dot-boxplot, with a task displaying data from samples in simple boxplots, and with a task displaying data in a stacked boxplot. Teachers used mode, minimum and maximum values, and central intervals of values to describe the distributions and used nonstandard terminology such as clustering, spread out, majority, and trend in their reasoning after using dotplots. Teachers struggled to represent quartiles on a dotplot, but their reasoning about variation improved by using boxplots.