Notice that these are already in order so you can presume \(y_1 = 0.6\) million is the minimum and \(y_{50} = 38.3\) million is the maximum. Therefore, the midrange is given by
\begin{equation*}
\frac{0.6+38.3}{2} = \frac{38.9}{2} = 19.45 \text{million}.
\end{equation*}
In this collection of "states" data the District of Columbia is included so that the number of data items is n=51. The mean of this data takes a bit of arithmetic but gives
\begin{equation*}
\overline{x} = \frac{\sum_{k=1}^{51} y_k }{51} = \frac{316.1}{51} \approx 6.20
\end{equation*}
million residents.