Figure 2
Null distributions affected by MDR modeling. The null distributions are estimated using 500 simulated null data sets. Each null data set contains n = 2000 samples. Upper panel: From left to right, each data set has L = 2, L = 3, L = 4 SNPs. MDR can be applied to these data sets without model search to fit the two-factor model (d = 2), the three-factor model (d = 3), and the four-factor model (d = 4). The resulting null distributions follows χ2 distributions with df = 4.84, 11.40, 30.41, respectively. Lower panel: Each null data set contains n = 2000 samples and L = 20 SNPs. MDR is directly applied to each data set. MDR searches all possible models and cross-validation is used to assess each model. The best two-factor model (d* = 2), the best three-factor model (d* = 3), and the best four-factor model (d* = 4) are identified. Their distributions, shown from left to right, do not strictly follow χ2 distributions.