3 Although the level of statistical significance is reported to be 99%, CIs in Figure 1(a) show that the proportion of each bootstrap distribution was substantially underestimated leading to overly narrow CI limits for both SAME and DIFF.
figure 1(b) shows CIs resulting from an accurately computed proportion of 95% of the same bootstrap distribution, where even at the lower level of 95% significance (as opposed to 99%) CIs for SAME and DIff now overlap, reversing the conclusion of strong reference bias.