OCR D2 2007 January — Question 3

Exam BoardOCR
ModuleD2 (Decision Mathematics 2)
Year2007
SessionJanuary
TopicGroups

3 Rebecca and Claire repeatedly play a zero-sum game in which they each have a choice of three strategies, \(X , Y\) and \(Z\). The table shows the number of points Rebecca scores for each pair of strategies. \begin{table}[h]
\captionsetup{labelformat=empty} \caption{Claire}
\(X\)\(Y\)\(Z\)
\cline { 2 - 5 }\(X\)5- 31
\cline { 2 - 5 } Rebecca\(Y\)32- 2
\cline { 2 - 5 }\(Z\)- 113
\cline { 2 - 5 }
\cline { 2 - 5 }
\end{table}
  1. If both players choose strategy \(X\), how many points will Claire score?
  2. Show that row \(X\) does not dominate row \(Y\) and that column \(Y\) does not dominate column \(Z\).
  3. Find the play-safe strategies. State which strategy is best for Claire if she knows that Rebecca will play safe.
  4. Explain why decreasing the value ' 5 ' when both players choose strategy \(X\) cannot alter the playsafe strategies.