After performing GWAS, I calculated the percentage of phenotypic variance (SNP-based heritability) for top SNPs and random SNPs using GREML (GCTA). The variance of random SNPs was calculated for 3 different groups of randomly chosen SNPs and then averaged to get the final result. Top SNPs explained much more variance then random (10% > 0.2%). I want to check if the difference is statistically significant.
Which significance test should I use for this?