\textbf{147 --} Referring to the relative frequency histogram of grouped quantitative data, what is the mean?
\textit{[Figure: A relative frequency histogram with data values 7, 12, 13, 17, 19 on the horizontal axis and relative frequencies approximately 12, 35, 18, 25, 10 on the vertical axis]}
\begin{itemize}
\item[(1)] $13$
\item[(2)] $13.8$
\item[(3)] $14$
\item[(4)] $14.2$
\end{itemize}