In the current study, the mean score of Group 3 was at the 84th percentile relative to Group 2, and the percentage
of non overlap between the group distributions was 55% (see Table 4). This result gives us a sense of how substantial the
difference is in group performance. The magnitude of the difference between the post-test scores of Group 1 and Group 3 was d = 2.7, another large effect size. In this case, more than 81% of the scores in the distribution of Group 3 did not
overlap with Group 1, and the percentile standing of Group 3 was more than 98% relative to Group 2 (Carson, n.d.).