Calculate the number of edges showing a nominally significant relationship with each covariate

[mbnebel]

nominally significant defined as p<.05 uncorrected

Use the info to answer @benjaminrisk's question about Figure 6

[mbnebel]

covariate_figures.Rmd now creates a table of edge counts for each covariate, stratified by motion QC level.

In the section 3.1.4 of the manuscript, I used the following (arbitrary) thresholds to describe Figure 6:

• <10 edges = no evidence of clustering
• 10-20 = some evidence
• <20 = evidence