| Code | Dose-Response Curve |
| blank | Either no dose-related effect, or no curve shape could be determined because experiment had only two dose groups including controls |
| * | Consistent with linearity |
| / | Significant departure from linearity, upward curvature |
| \ | Significant departure from linearity, downward curvature |
| Z |
Significant departure from linearity, more than three dose groups including controls For \ and Z, if there was significant downward departure from linearity, the TD50 was calculated without the data from the highest dose groups(s). In the plot, parentheses around the tumor incidence for a dose group indicate that the data were omitted from the final TD50 calculation. |