$$y＝f（x|{\nu }_1，{\nu }_2）＝\frac{\Gamma ［\frac{（{\nu }_1+{\nu }_2）}{2}］}{\Gamma （\frac{{\nu }_1}{2}）\Gamma （\frac{{\nu }_2}{2}）}{（\frac{{\nu }_1}{{\nu }_2}）}^{\frac{{\nu }_1}{2}}\frac{x^{\frac{{\nu }_1-2}{2}}}{{［1+（\frac{{\nu }_1}{{\nu }_2}）x］}^{\frac{{\nu }_1+{\nu }_2}{2}}}$$

$$F（{\nu }_1，{\nu }_2）＝\frac{\raisebox{1ex}{${\chi }_1$}\!\left/ \!\raisebox{-1ex}{${\nu }_1$}\right.}{\raisebox{1ex}{${\chi }_2$}\!\left/ \!\raisebox{-1ex}{${\nu }_2$}\right.}$$