CAIE S1 2020 June — Question 1

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2020
SessionJune
TopicGeometric Distribution
TypeCompound event with two dice/coins

1 The score when two fair six-sided dice are thrown is the sum of the two numbers on the upper faces.
  1. Show that the probability that the score is 4 is \(\frac { 1 } { 12 }\).
    The two dice are thrown repeatedly until a score of 4 is obtained. The number of throws taken is denoted by the random variable \(X\).
  2. Find the mean of \(X\).
  3. Find the probability that a score of 4 is first obtained on the 6th throw.
  4. Find \(\mathrm { P } ( X < 8 )\).