OCR MEI Further Statistics B AS 2019 June — Question 2

Exam BoardOCR MEI
ModuleFurther Statistics B AS (Further Statistics B AS)
Year2019
SessionJune
TopicDiscrete Probability Distributions
TypeConstruct probability distribution from scenario

2 Leila and Caleb are playing a game, using fair six-sided dice and unbiased coins.
  • Leila rolls two dice, and her score \(L\) is the total of the scores on the two dice.
  • Caleb spins 4 coins and his score \(C\) is three times the number of heads obtained.
The winner of a game is the player with the higher score. If the two scores are equal, the result of the game is a draw. The spreadsheet in Fig. 2 shows a simulation of 20 plays of the game. \begin{table}[h]
ABCDEFGH
1First diceSecond diceTotal (Leila's score) \(\boldsymbol { L }\)Coin 1Coin 2Coin 3Coin 4Caleb's score \(\boldsymbol { C }\)
2123HTTT3
3617THTT3
4268HHTT6
5257THHH9
6156THTT3
7527HHHH12
8112HTHT6
9268THTH6
10628HTHT6
11134THHH9
12617THTT3
13314TTTT0
14369HTHH9
15235THHH9
16257HHHH12
17156HHTH9
185611THHH9
19426THHT6
206511TTHH6
21112TTTT0
\captionsetup{labelformat=empty} \caption{Fig. 2}
\end{table}
  1. Explain why the value of \(C\) in row 2 is 3 .
  2. Use the spreadsheet to estimate \(\mathrm { P } ( C > 6 )\) and \(\mathrm { P } ( L > 6 )\).
  3. Use the spreadsheet to estimate the probability that Leila loses a randomly chosen game.
  4. Explain why your answers to parts (b) and (c) may not be very close to the true values.
  5. Leila claims that the game is fair (that Leila and Caleb each have an equal chance of winning) because both she and Caleb can get a maximum score of 12 and also in the simulation she won exactly \(50 \%\) of the games.
    Make 2 comments about Leila’s claim.