“…These changes urge us to reconsider curricular learning experiences (Watson, 2017). To gain a fuller picture in the presentation of measures of center in the textbooks, there is a need to extend Cai et al (2002)'s study by considering recent studies in measures of center conducted in educational settings, which gave clues about learning trajectories for teaching measures of center (Bakker et al, 2006;Büscher & Schnell, 2017;Makar, 2014) and other crucial elements in teaching statistical concepts including measures of center such as contextual features (e.g., real, authentic context) (Gal, 1995;Makar, 2014;Watson, 2016), graphical displays (Pfannkuch et al, 2010), and technological tools (Bakker et al, 2006;Watson, 2016). Furthermore, international comparison studies would inform countries by pointing to the ways of developing their current curriculum materials (Watson, 2017).…”