This paper analyses technology-based instruction on data-analysis with box plots. Examples of instruction taken from the research literature inform a study of two classes of 17 year-old students (upper secondary) in which the mathematical relationships that their teachers targeted are distinguished as being, or not being, relevant to statistical analysis. In analysing the features of technologies, the paper identifies the potential of displaying dot plots and corresponding box plots on the same screen display as being a particularly powerful way of motivating new interpretations of data structures for learners.