OCR MEI S1 2010 January — Question 1

Exam BoardOCR MEI
ModuleS1 (Statistics 1)
Year2010
SessionJanuary
TopicMeasures of Location and Spread
TypeConstruct stem-and-leaf then find median and quartiles

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