Pharmaceutical Statistics Using SAS

5.4. Power Evaluation in a Two-Factor Model for Qt Interval

This section describes the process of estimating the power of a trend test in a two-factor ANOVA model. The application is for a general toxicology study in beagle dogs with a vehicle control (Dose 0) and three groups of increasing doses of a compound (Doses 1, 2 and 3). A sample size of three or four animals per sex per group is generally used. The purpose of the analysis is to evaluate the treatment effects on heart rate-corrected QT intervals by identifying the highest no effect dose level (NOEL). The power evaluation is important because the recent ICH S7B guideline (2004) recommends that the sensitivity and reproducibility of the in vivo test system should be characterized. See ...