ワイブル分布（パーセント点）

\(\normalsize Weibull\ distribution\\ (1)\ probability\ density\\ \hspace{30px}f(x,a,b)={\large\frac{a}{b}(\frac{x}{b})^{a-1}e^{-(\frac{x}{b})^a}}\\ (2)\ lower\ cumulative\ distribution\\ \hspace{30px}P(x,a,b)={\large\int_{\small 0}^{\small x}}f(t,a,b)dt={\large 1-e^{-(\frac{x}{b})^a}}\\ (3)\ upper\ cumulative\ distribution\\ \hspace{30px}Q(x,a,b)={\large \int_{\small x}^{\small\infty}}f(t,a,b)dt={\large e^{-(\frac{x}{b})^a}}\\\)