CAIE S1 2022 November — Question 5

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2022
SessionNovember
TopicTree Diagrams
TypeRepeated trials until stopping condition

5 A game is played with an ordinary fair 6-sided die. A player throws the die once. If the result is \(2,3,4\) or 5 , that result is the player's score and the player does not throw the die again. If the result is 1 or 6 , the player throws the die a second time and the player's score is the sum of the two numbers from the two throws.
  1. Draw a fully labelled tree diagram to represent this information. Events \(A\) and \(B\) are defined as follows.
    \(A\) : the player's score is \(5,6,7,8\) or 9
    \(B\) : the player has two throws
  2. Show that \(\mathrm { P } ( A ) = \frac { 1 } { 3 }\).
  3. Determine whether or not events \(A\) and \(B\) are independent.
  4. Find \(\mathrm { P } \left( B \mid A ^ { \prime } \right)\).