Stepwise Confidence Intervals Procedures for Toxicological Studies from Grouped Samples

In toxicological studies,it is desirable for a method to not declare a higher dose to be safe if it does not declare a lower dose to be safe, Hsu and Berger(1999)and Tao,Guo and Shi(2002)´s stepwise confidence interval method were recently proposed for this purpose.However, their procedure necessitates the exact values of the observations under normal population. In this article, we propose a stepwise confidence interval method from grouped samples. In addition, we have given a proof that the family-wise type I rate can be controlled at the pre-chosen nominal level. An example is used to illustrate our method.