In the study of survival endpoints, the size of the sample is crucial. The calculation of the sample size for survival endpoints was first proposed and presented by Freedman based on the logrank statistic. Later, many statisticians gradually introduced multiple factors such as dropout rate and delayed onset, proposed various estimation methods including the lrstat method, and developed corresponding statistical programs. However, the application of professional statistical functions is relatively complex. Based on this, this paper has developed a corresponding visual web application on the basis of the R package lrstat and powerSurvEpi, and tested its functions and program accordingly. The test results are basically consistent with the case, proving the effectiveness of the application.

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