“…Subjects' judgments of statistical association in a variety of situations have been investigated by researchers in social psychology (e.g., Alloy & Tabachnik, 1984;Crocker, 1981), science education (e.g., Donnelly & Welford, 1989;Swatton, 1994;Swatton & Taylor, 1994), and statistics education (e.g., Batanero, Estepa, & Godino, 1997). Many studies have followed Inhelder and Piaget (1958) in considering association of dichotomous variables in contingency tables, whereas few have considered covariation of two numerical variables .…”