Figure 2.

The empirical power of the approximate F-distribution test of model (3) using B-spline basis based on Pillai–Bartlett trace and SKAT-O at α = 0.01, when causal variants were only rare and 10% of the variants were causal. For the trait y₁, 20%/80% causal variants had negative/positive effects; pct2 represents the percentage of negative effect causal variants for trait y₂; and pct3 represents the percentage of negative effect causal variants for trait y₃.