4 A camera records the speeds in miles per hour of 15 vehicles on a motorway. The speeds are given below.
$$\begin{array} { l l l l l l l l l l l l l l l }
73 & 67 & 75 & 64 & 52 & 63 & 75 & 81 & 77 & 72 & 68 & 74 & 79 & 72 & 71
\end{array}$$
- Construct a sorted stem and leaf diagram to represent these data, taking stem values of \(50,60 , \ldots\).
- Write down the median and midrange of the data.
- Which of the median and midrange would you recommend to measure the central tendency of the data? Briefly explain your answer.