Sentence examples for median item difficulty from inspiring English sources
As this parameter did not fit the normal distribution Shapiro-Wilks W == .910, p < .001; Fig. 2a), comparison of median item difficulty within each group was performed by means of the Mann–Whitney- U test.
We initially examined whether the inclusion of an image within the item stem altered the item difficulty using Mann Whitney U. The median item difficulty for images with purely textual stems was 0.77, while that for items within which an appropriate image was included was 0.80 (Fig. 3); this difference was not significant (0.77 vs. 0.80; p = 0.862, Mann–Whitney-U = 4818.5; Fig. 3).
We initially examined whether the inclusion of an image within the item stem altered the item difficulty using Mann Whitney U. The median item difficulty for images with purely textual stems was 0.77, while that for items incorporating an appropriate image was 0.80; this difference was not significant (0.77 vs. 0.80; p = 0.862, Mann–Whitney-U = 4818.5).
Furthermore, light propagation is an easier content topic (average item difficulty = −0.53) than visibility (average item difficulty = −0.10).
Additionally, the overall difficulties reveal that tier 1 is quite easy (average item difficulty = −0.61) compared to tier 2 (average item difficulty = −0.02).
Values of item difficulty were on average 37 (Range: 6 – 58), indicating moderate to difficult item difficulties.
Two common reliability tests are item difficulty and item discrimination.
Analyses of item difficulty, item discrimination and generalizability indicated that the eLCQC provides high-quality evaluations.
Content validity, item reliability (test retest, item-total correlation, item difficulty) and test reliability (internal consistency) were established.
b i item difficulty, SE standard error.
