Pharmaceutical Statistics Using SAS

10.3. p-Values, α, β and Power

The primary efficacy analysis will yield a p-value that compares the mortality rates of control versus QCA. Smaller p-values indicate greater statistical separation between the two samples, but how that p-value is determined is an issue that is not critical to understanding the essential concepts in sample-size analysis. In this case, that p-value may come from one of the many methods to compare two independent proportions, including the likelihood ratio chi-square test, as used here, or it may come from a logistic or hazard modeling that includes co-predictors. Regardless of what test is used to get the p-value, if p is small enough ("significant") and the QCA mortality rates are better, Dr. Capote will report ...