Comparison of BMD values for WSSs in the mouse lymphoma assay. The BMD (BMD10, BMD50, BMD100, and BMD200) estimates producing a 10%, 50%, 100%, or 200% increase in the background frequency were calculated using exponential model of PROAST both without (A,B,C,D) and with covariate analysis approach (E,F,G,H). The bars represent the calculated 95% confidence interval of each value. The lower and upper limits derived from the BMD estimates were used to differentiate between responses based on non-overlapping confidence intervals.