Use the Frequency Distribution to Find the Mean and the Sample

Multiple Choice

Use the frequency distribution to find the mean and the sample standard deviation. Does the data form a normal distribution? Remember: if the data fall within 2% of the empirical rule of 68%, 95%, and 99.7% for one, two, or three standard deviations, respectively, they form a normal distribution.   $\begin{array} { | l | l | } \hline \text { Shipment time (hours) } & \text { Frequency } f \\\hline 23.5 - 28.5 & 19 \\\hline 28.5 - 33.5 & 417 \\\hline 33.5 - 38.5 & 789 \\\hline 38.5 - 43.5 & 698 \\\hline 43.5 - 48.5 & 504 \\\hline 48.5 - 53.5 & 42 \\\hline\end{array}$

A) The mean is 45 hours. The sample standard deviation is 5 hours. The data doesn't form a normal distribution.
B) The mean is 39 hours. The sample standard deviation is 5 hours. The data doesn't form a normal distribution.
C) The mean is 39 hours. The sample standard deviation is 5 hours. The data forms a normal distribution.
D) The mean is 35 hours. The sample standard deviation is 5 hours. The data doesn't form a normal distribution.
E) The mean is 45 hours. The sample standard deviation is 5 hours. The data forms a normal distribution.