nTerim 1.1.1 is free to download from our software library. The software is categorized as Business Tools. The following version: 1.1 is the most frequently downloaded one by the program users. The common filename for the program's installer is NQInterimAnalysis.exe. This tool was originally developed by Statistical Solutions Ltd. The latest version of the program can be installed on PCs running Windows XP/Vista/7/8/10, 32-bit.
From the developer:
Power and Sample Size for Group Sequential Trials. The main features of this product are: Power and Sample Size calculations for Two Means test, Two Proportions test and Log Rank test.
Choice of four alpha spending functions, O’Brien-Fleming, Pocock, Hwang-Shih-DeCani and Power as well as option to manually specify boundaries. Plots of boundary values. Plots of power vs sample size.
You may want to check out more software, such as nQuery Advisor + nTerim, which might be similar to nTerim.