We linked self-efficacy measurements to the content of each of the two courses. To
derive the self-efficacy items, we selected specific topic tasks in the courses with the
help of the courses’ instructor.
We used the first 10 conceptual tasks (i.e., those requiring no mathematical skills) to write the final scale items. We consulted Bandura’s (2006) ‘‘Guide for Constructing Self-Efficacy Scales’’ to construct the item scales. The statistical tasks in the scales matched the statistical reasoning ability measures at the end of the courses.