A psychologist records the duration of natural labor (in hours) in a sample of 36 first-pregnancy mothers. Based on the duration data given in the following table, which measure of central tendency is most appropriate for describing these data?
$$
\begin{aligned}
&\begin{array}{|l|l|l|l|}
\hline 1 & 5 & 6 & 2 \\
\hline 7 & 3 & 4 & 7 \\
\hline & & &
\end{array}\\
&\begin{array}{|l|l|l|l|}
\hline 10 & 7 & 5 & 6 \\
\hline 4 & 3 & 2 & 11 \\
\hline 5 & 9 & 8 & 5 \\
\hline 6 & 6 & 9 & 7 \\
\hline 4 & 5 & 6 & 4 \\
\hline 8 & 8 & 10 & 9 \\
\hline 8 & 7 & 6 & 3
\end{array}
\end{aligned}
$$