$$\mathrm{W.}（\mathrm{N.}的）=\frac{{\mathrm{一世}}_{0.}（\beta \sqrt{1-{（\frac{\mathrm{N.}-\mathrm{N.}/2}{\mathrm{N.}/2}的）}^2}的）}{{\mathrm{一世}}_{0.}（\beta 的）}那0.\le .\mathrm{N.}\le .\mathrm{N.}那$$

$$\beta =\{\begin{array}{ll}0.1102（\alpha -8.7的）那\hfill & \alpha >50.\hfill \\ 0.5842{（\alpha -21.的）}^{\mathrm{0．4}}+\mathrm{0.07886.}（\alpha -21.的）那\hfill & 50.\ge \alpha \ge 21.\hfill \\ 0.那\hfill & \alpha <21.\hfill \end{array}$$