Formula 1 k99=2.326+exp[1.34−0.522ln(n)+3.87/n]\mathrm{k}_{99}=2.326+\exp \left[1.34-0.522 \ln (\mathrm{n})+3.87 / \mathrm{n}\right]k99=2.326+exp[1.34−0.522ln(n)+3.87/n] Formula 2 k90=1.282+exp[0.958−0.520ln(n)+3.19/n]\mathrm{k}_{90}=1.282+\exp \left[0.958-0.520 \ln (\mathrm{n})+3.19 / \mathrm{n}\right]k90=1.282+exp[0.958−0.520ln(n)+3.19/n]