CAIE S1 2022 November — Question 4

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2022
SessionNovember
TopicGeometric Distribution
TypeNon-geometric distribution identification

4 Three fair 4-sided spinners each have sides labelled 1,2,3,4. The spinners are spun at the same time and the number on the side on which each spinner lands is recorded. The random variable \(X\) denotes the highest number recorded.
  1. Show that \(\mathrm { P } ( X = 2 ) = \frac { 7 } { 64 }\).
  2. Complete the probability distribution table for \(X\).
    \(x\)1234
    \(\mathrm { P } ( X = x )\)\(\frac { 7 } { 64 }\)\(\frac { 19 } { 64 }\)
    On another occasion, one of the fair 4 -sided spinners is spun repeatedly until a 3 is obtained. The random variable \(Y\) is the number of spins required to obtain a 3 .
  3. Find \(\mathrm { P } ( Y = 6 )\).
  4. Find \(\mathrm { P } ( Y > 4 )\).