From the data set
\begin{equation*}
x_1, x_2, ... , x_n,
\end{equation*}
assume that when sorted it is denoted
\begin{equation*}
y_1, y_2, ..., y_n
\end{equation*}
where
\begin{equation*}
y_1 \le y_2 \le ... \le y_n.
\end{equation*}
Then, \(y_k\) is known as the kth order statistic.