Fig. 4

Wright Map on the 12 items of the bMCU test and the N = 249 students. The left panel provides the distribution of the students’ person parameters (ability), and the right panel depicts the location of each item’s difficulty parameter along the same latent dimension. From bottom to top, person ability and item difficulty increase. The gray bar on the latent dimension axis in the left panel indicates the range of values where approximately 68% of all person parameters are located. The black square in the middle of the bar marks the mean of all person parameters, the black squares at the upper and lower end of the bar correspond to the mean plus and minus one standard deviation. The two more extreme black squares on the latent dimension axis correspond to the mean plus and minus two standard deviations. Approximately 95% of all person parameters are located between these two squares. The two horizontal lines in the right panel correspond to the mean of the item parameters (i.e., M = 0) plus and minus one standard deviation, indicating the range of values where approximately 68% of all item parameters are located. The map shows that the items are reasonably spread across the students’ ability range, with most items covering the average ability range, in which most students are located