OCR MEI Further Statistics Minor 2019 June — Question 1

Exam BoardOCR MEI
ModuleFurther Statistics Minor (Further Statistics Minor)
Year2019
SessionJune
TopicBinomial Distribution
TypeBasic E(X) and Var(X) calculation

1 In a game at a charity fair, a spinner is spun 4 times.
On each spin the chance that the spinner lands on a score of 5 is 0.2 .
The random variable \(X\) represents the number of spins on which the spinner lands on a score of 5 .
  1. Find \(\mathrm { P } ( X = 3 )\).
  2. Find each of the following.
    • \(\mathrm { E } ( X )\)
    • \(\operatorname { Var } ( X )\)
    One game costs \(\pounds 1\) to play and, for each spin that lands on a score of 5 , the player receives 50 pence.
    1. Find the expected total amount of money gained by a player in one game.
    2. Find the standard deviation of the total amount of money gained by a player in one game.