SPS SPS FM Statistics 2021 January — Question 6

Exam BoardSPS
ModuleSPS FM Statistics (SPS FM Statistics)
Year2021
SessionJanuary
TopicGeometric Distribution
TypeP(X ≤ n) or P(X < n)

6. A spinner can land on red or blue. When the spinner is spun, there is a probability of \(\frac { 1 } { 3 }\) that it lands on blue. The spinner is spun repeatedly. The random variable \(B\) represents the number of the spin when the spinner first lands on blue.
  1. Find (i) \(\mathrm { P } ( B = 4 )\)
    (ii) \(\mathrm { P } ( B \leqslant 5 )\)
  2. Find \(\mathrm { E } \left( B ^ { 2 } \right)\) Steve invites Tamara to play a game with this spinner.
    Tamara must choose a colour, either red or blue.
    Steve will spin the spinner repeatedly until the spinner first lands on the colour Tamara has chosen. The random variable \(X\) represents the number of the spin when this occurs. If Tamara chooses red, her score is \(\mathrm { e } ^ { X }\)
    If Tamara chooses blue, her score is \(X ^ { 2 }\)
  3. State, giving your reasons and showing any calculations you have made, which colour you would recommend that Tamara chooses.