Parental-monitoring scores ranged from 0.0 to 2.0 (M = 1.65, SD = 0.369). The mean externalizing score ranged from 0.62 to 31.36 (M = 9.42, SD = 5.42). Table 1 shows results for the unconditional main effect of each SNP and for the interactions between SNP and parental monitoring. No SNPs had significant main effects of association with externalizing behavior. There was a significant main effect of parental monitoring (p ≤ .001, β = −0.328). Parental monitoring also moderated the effects of CHRM2 on externalizing behavior in the case of three of the nine SNPs (p = .017–.045), and the interaction showed a trend toward significance for one additional SNP (p = .081). It is not straightforward to correct for multiple tests in genetic studies that test multiple genetic variants across a gene because these variants are correlated with one another, which makes straightforward Bonferroni correction inappropriate. The genetic analysis program Plink (Purcell et al., 2007) has implemented a permutation approach that gives a set-based empirical p value indicating the likelihood of observing the pattern of p values across the
