Find the Mean of the Data Summarized in the Given

Multiple Choice

Find the mean of the data summarized in the given frequency distribution.
-The manager of a bank recorded the amount of time each customer spent waiting in line during peak business hours one Monday. The frequency distribution below summarizes the results. Find the mean waiting time. Round your answer to one decimal place.
$$\begin{array} { r | r } \begin{array} { c } \text { Waiting time } \\\text { (minutes) }\end{array} & \begin{array} { c } \text { Number of } \\\text { customers }\end{array} \\\hline 0 - 3 & 14 \\4 - 7 & 13 \\8 - 11 & 14 \\12 - 15 & 8 \\16 - 19 & 6 \\20 - 23 & 3 \\24 - 27 & 3\end{array}$$

A) 9.7 min
B) 13.5 min
C) 9.5 min
D) 8.7 min