Level 2: Inadequate Covariation. Thirty-four students showed some features of the
required negative covariation but lacked either appropriate variation or appropriate
correspondence. Fifteen students treated study time as a binary variable, five
students giving a double comparison involving two bivariate pairs (e.g., Figure 6a,
G7m) and 10 representing a group comparison including test scores of six students
(e.g., Figure 6b, G3f). Nineteen students did not adequately show the direction of
covariation, nine failing to clearly indicate any covariation (e.g., Figure 6c, G7m),
seven representing a positive covariation (e.g., Figure 6d, G5f), and three showing a
negative trend with some explicit numbers but without labels or units to indicate the
variables, such as a pie graph with larger sectors corresponding to labels of smaller
percentage values.