An example for tan-correction. Expected RAS value distribution (y-axis) depending on observed RAS values (x-axis) modeled using arctangent functions as described in the methods section. In this example, the mean RAS values (correction values) of the BB, AB and AA genotypes were set to 0.15, 0.55 and 0.8, respectively, and labeled by crosses. The gray diagonal corresponds to the tan-corrected RAS values. The black solid, dotted and dashed lines represent the model function by setting the parameter n to the values of 0.5, 1 and 2, respectively.