The most recent xkcd illustrates the problem of multiple comparisons: (As usual, click on the image for a larger version.) After 14 more "not significant" results, The mouseover title: "'So, uh, we did the green study again and got no link. It was probably a–' 'RESEARCH CONFLICTED ON GREEN JELLY BEAN/ACNE LINK; MORE STUDY RECOMMENDED!'" … Continue reading Bonferroni rules