# Kengo Nagashima

## Brief description

This web application is an implementation of sample size determination method for the log-rank test of non-inferiority (Jung & Chow, 2012), assuming the proportional hazards assumption holds. This app is implemented in JavaScript, and it does not collect any information from user input.

Standard MST, Accural time, Follow-up time: You should unify time unit (year or month).

Allcation ratio: When the ratio, $r \gt 1$, sample size of test group is larger than of standard group ($n_{\mathrm{test}} = r n_{\mathrm{std}}$). For instance, when $r = 2$, $n_{\mathrm{test}} = 2 n_{\mathrm{std}}$.

Non-inferiority margin: $\Delta_0$ is a hazard ratio for null hypothesis. You may input $HR \lt \Delta_0$.

Of course, only one-sided test is supported.

## References

1. Jung SH, Chow SC. On sample size calculation for comparing survival curves under general hypothesis testing. Journal of Biopharmaceutical Statistics 2012;22(3):485–495. [Web Site]