See this vignette if you want to understand how group sequential design probabilities are calculated and gain an intuitive understanding of the underlying methods.
Start here if this is your first time using GroupSeq. This vignette gives a brief overview of what can be done with GroupSeq.
This vignette shows how to use GroupSeq to compute group sequential designs under the null hypothesis, introduces all available options and discusses some nuances of certain design types.
This vignette shows how to use GroupSeq to compute group sequential designs with a certain power and how to interpret the results.
This vignette shows how to use GroupSeq to compute group sequential probabilities under both H0 or H1.
This vignette shows how to use GroupSeq to compute confidence intervals at the final stage of a group sequential analysis.