Fig. 5.

Multiple testing correction. a Family-wise error rate (FWER). When multiple items (flowers) are observed, their values (heights) vary. The tallest flower in each group can be significantly tall, but its height should not be used for judgment. The height should be judged among the tallest flowers from many groups. This method of significance judgment is applied to the interpretation of the rarity of p values and is referred to as FWER correction. b In (a) there are only four flowers in a group. (b) has many more flowers. The FWER applies the same cut-off value (red line) to all flowers, and the first and second tallest flowers are judged to be significantly deviated. The false-discovery rate method applies different cut-off values (blue line) depending on the rank of the flowers and the top four flowers are judged to be significantly deviated