Formula 1 F−1(P/100)=τ50+α50[−ln(1−(P/100))]β50\mathrm{F}^{-1}(\mathrm{P} / 100)=\tau_{50}+\alpha_{50}\left[-\ln \left(1-(\mathrm{P} / 100)\right)\right]^{\beta_{50}}F−1(P/100)=τ50+α50[−ln(1−(P/100))]β50