### Confidence levels and relevant probabilities

Hypothetical Data for Kil-EZ Carcinogenicity Test Number of test rats Number of rats with tumors Rat test dose in mg Kil-EZ per kg rat body weight (mg/kg/day) Probability of a rat's developing tumors Lower 95% confidence level Upper 95% confidence level 50 1 0 .02 50 5 20 .10 50 10 40 .20 50 20 80 .40 50 7* 160 .