Threshold selection using permutation testing Estimating the number of incorrect edges from the number of edges found in permuted data sets for the ALARM network. The horizontal axis is the frequency threshold above which an edge is said to be present. The vertical axis is the number of edges. The dashed blue line is the number of correct edges. The dashed red line is the number of incorrect edges. The faint purple lines are the number of edges found for each of 60 independent permuted data sets. Overlapping lines are darker in proportion to the number of lines involved. The solid red line is the average number of edges found in the permuted data sets.