FIGURE 5.

Experimental design skills observed on pretest and posttest for students in different quartiles. The observed experimental design skills are the percentage of students whose response to the EDAT prompt included a given rubric category in study 2. The categories on the x-axis represent the EDAT scoring rubric items (Table 2) listed in the order of experimental design sophistication (Sirum and Humburg, 2011). Categories in bold font are components of the basic understanding score, and those in capital letters are components of the advanced understanding score based on Shanks et al. (2017). The sample size was 145 students from nine courses at six different institutions.