The random variable \(\xi\) has a continuous distribution function \(F(x)\). As a result of \(n\) independent observations of \(\xi\), we have the following values \(x_{1}

\[ \eta=\frac{F\left(x_{n}\right)-F\left(x_{2}\right)}{F\left(x_{n}\right)-F\left(x_{1}\right)} \]