¹²The 95% CI estimation: Defining $p$ to be the empirical survival-ratio out of $n$ samples, we set $\alpha =0.05$ in $p\pm z_{\alpha ∕2}\left(\sqrt{p(1-p)∕n}\right)=p\pm 1.96\left(\sqrt{p(1-p)∕n}\right)$ to obtain the CI.