Fig. 3
From: Towards a science inquiry test in primary education: development of items and scales
The WrightMap presenting difficulty of SIT-PE items and distribution of student abilities. M on the left side of the vertical scale—average ability of students participating in the study. M on the right side of the vertical scale—average difficulty of items included in the study. S on the left side of the vertical scale—one standard deviation from the average ability of students. S on the right side of the vertical scale—one standard deviation from the average difficulty of items. T on the left side of the vertical scale—two standard deviations from the average ability of students. T on the right side of the vertical scale—two standard deviations from the average difficulty of items