Edexcel S1 2024 June — Question 6 13 marks

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2024
SessionJune
Marks13
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPrinciple of Inclusion/Exclusion
TypeThree-Set Venn Diagram Probability Calculation
DifficultyStandard +0.3 This is a standard S1 Venn diagram question with straightforward probability calculations. Part (a) requires simple addition of regions, (b)-(c) use independence to set up basic equations, and (d)-(e) involve routine probability operations. While multi-part, each step follows directly from definitions without requiring novel insight or complex problem-solving.
Spec2.03a Mutually exclusive and independent events2.03b Probability diagrams: tree, Venn, sample space2.03c Conditional probability: using diagrams/tables2.03d Calculate conditional probability: from first principles

  1. The Venn diagram shows the probabilities related to teenagers playing 3 particular board games. \(C\) is the event that a teenager plays Chess \(S\) is the event that a teenager plays Scrabble \(G\) is the event that a teenager plays Go
    where \(p\) and \(q\) are probabilities. \includegraphics[max width=\textwidth, alt={}, center]{ee0c7c12-84f3-479c-b36a-3357f8529a1c-22_684_935_598_566}
    1. Find the probability that a randomly selected teenager plays Chess but does not play Go.
    Given that the events \(C\) and \(S\) are independent,
  2. find the value of \(p\)
  3. Hence find the value of \(q\)
  4. Find (i) \(\mathrm { P } \left( ( C \cup S ) \cap G ^ { \prime } \right)\) (ii) \(\mathrm { P } ( C \mid ( S \cap G ) )\) A youth club consists of a large number of teenagers.
    In this youth club 76 teenagers play Chess and Go.
  5. Use the information in the Venn diagram to estimate how many of the teenagers in the youth club do not play Scrabble.

Question 6:
Part (a):
AnswerMarks Guidance
Answer/WorkingMark Guidance
0.16 oeB1 Correct probability
Part (b):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\([P(C)=] 0.04+0.15+0.12+p [=0.31+p]\); \([P(S)=] 0.1+0.15+0.12+0.23[=0.6]\); \([P(S \cap C)=] 0.15+0.12[=0.27]\)M1 For 2 correct probability expressions
All three expressions correct; \([P(C')=] 0.1+0.23+q[=0.33+q]\); \([P(S')=]0.4\); \([P(S'\cap C')=]q\)M1 All 3 correct probability expressions; allow \(P(C)=0.45\)
\((\text{"0.31"}+p)\times\text{"0.6"} = \text{"0.27"}\) oe; or \((\text{"0.33"}+q)\times\text{"0.4"} = q\) oeM1d Dependent on 1st M1; for use of \(P(C\cap S)=P(C)\times P(S)\) or \(P(C'\cap S')=P(C')\times P(S')\) ft their probabilities if labelled clearly
\(p = 0.14\) oe; \(q = 0.22\) oeA1 For 0.14 or exact equivalent or 0.22 or exact equivalent
Part (c):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(q = 1-(0.04+0.12+0.15+0.1+0.23+\text{"p"})\); or \(p = 1-(0.04+0.12+0.15+0.1+0.23+\text{"q"})\)M1 For correct expression for \(q\) ft their \(p\) or correct expression for \(p\) ft their \(q\)
\(q = 0.22\) oe; \(p = 0.14\) oeA1ft For 0.22 or exact equivalent ft their \(p\), or 0.14 or exact equivalent ft their \(q\) (\(p+q=0.36\) provided \(p\) and \(q\) are probabilities)
Part (d)(i):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\([P((C \cup S) \cap G')] = 0.39\) oeB1 For 0.39 or exact equivalent; do not allow \(0.04+0.12+0.23\)
Part (d)(ii):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(P(C \mid (S \cap G)) = \frac{0.15}{0.15+0.1}\)M1 For \(\frac{0.15}{0.15+0.1}\)
\(= 0.6\) oeA1 For 0.6 or exact equivalent
Part (e):
AnswerMarks Guidance
Answer/WorkingMark Guidance
Number of teenagers \(= \frac{76}{0.15+\text{"p"}}\) oeM1 Relating 76 to their \(P(C \cap G)\); may be implied by awrt 262
Number who don't play Scrabble \(= \text{"}\!\left(\frac{76}{0.15+p}\right)\!\text{"} \times 0.4\ (= 104.8\ldots)\)M1 For number of teenagers \(\times 0.4\) ft their number of teenagers e.g. \(0.4 \times \text{"262"}\); provided number of teenagers is not 76
\(= 104.8\ldots\) awrt 105A1 awrt 105 ISW
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# Question 6:

## Part (a):
| Answer/Working | Mark | Guidance |
|---|---|---|
| 0.16 oe | B1 | Correct probability |

## Part (b):
| Answer/Working | Mark | Guidance |
|---|---|---|
| $[P(C)=] 0.04+0.15+0.12+p [=0.31+p]$; $[P(S)=] 0.1+0.15+0.12+0.23[=0.6]$; $[P(S \cap C)=] 0.15+0.12[=0.27]$ | M1 | For 2 correct probability expressions |
| All three expressions correct; $[P(C')=] 0.1+0.23+q[=0.33+q]$; $[P(S')=]0.4$; $[P(S'\cap C')=]q$ | M1 | All 3 correct probability expressions; allow $P(C)=0.45$ |
| $(\text{"0.31"}+p)\times\text{"0.6"} = \text{"0.27"}$ oe; or $(\text{"0.33"}+q)\times\text{"0.4"} = q$ oe | M1d | Dependent on 1st M1; for use of $P(C\cap S)=P(C)\times P(S)$ or $P(C'\cap S')=P(C')\times P(S')$ ft their probabilities if labelled clearly |
| $p = 0.14$ oe; $q = 0.22$ oe | A1 | For 0.14 or exact equivalent or 0.22 or exact equivalent |

## Part (c):
| Answer/Working | Mark | Guidance |
|---|---|---|
| $q = 1-(0.04+0.12+0.15+0.1+0.23+\text{"p"})$; or $p = 1-(0.04+0.12+0.15+0.1+0.23+\text{"q"})$ | M1 | For correct expression for $q$ ft their $p$ or correct expression for $p$ ft their $q$ |
| $q = 0.22$ oe; $p = 0.14$ oe | A1ft | For 0.22 or exact equivalent ft their $p$, or 0.14 or exact equivalent ft their $q$ ($p+q=0.36$ provided $p$ and $q$ are probabilities) |

## Part (d)(i):
| Answer/Working | Mark | Guidance |
|---|---|---|
| $[P((C \cup S) \cap G')] = 0.39$ oe | B1 | For 0.39 or exact equivalent; do not allow $0.04+0.12+0.23$ |

## Part (d)(ii):
| Answer/Working | Mark | Guidance |
|---|---|---|
| $P(C \mid (S \cap G)) = \frac{0.15}{0.15+0.1}$ | M1 | For $\frac{0.15}{0.15+0.1}$ |
| $= 0.6$ oe | A1 | For 0.6 or exact equivalent |

## Part (e):
| Answer/Working | Mark | Guidance |
|---|---|---|
| Number of teenagers $= \frac{76}{0.15+\text{"p"}}$ oe | M1 | Relating 76 to their $P(C \cap G)$; may be implied by awrt 262 |
| Number who don't play Scrabble $= \text{"}\!\left(\frac{76}{0.15+p}\right)\!\text{"} \times 0.4\ (= 104.8\ldots)$ | M1 | For number of teenagers $\times 0.4$ ft their number of teenagers e.g. $0.4 \times \text{"262"}$; provided number of teenagers is not 76 |
| $= 104.8\ldots$ awrt 105 | A1 | awrt 105 ISW |

The image appears to be essentially blank — it only contains the *PMT* header and the Pearson Education Limited footer with their registered company details.

There is **no mark scheme content** visible on this page. It appears to be either a blank page or the final/back page of a mark scheme document.

Could you share the pages that contain the actual mark scheme questions and answers? I'd be happy to extract and format that content for you.
\begin{enumerate}
  \item The Venn diagram shows the probabilities related to teenagers playing 3 particular board games.\\
$C$ is the event that a teenager plays Chess\\
$S$ is the event that a teenager plays Scrabble\\
$G$ is the event that a teenager plays Go\\
where $p$ and $q$ are probabilities.\\
\includegraphics[max width=\textwidth, alt={}, center]{ee0c7c12-84f3-479c-b36a-3357f8529a1c-22_684_935_598_566}\\
(a) Find the probability that a randomly selected teenager plays Chess but does not play Go.
\end{enumerate}

Given that the events $C$ and $S$ are independent,\\
(b) find the value of $p$\\
(c) Hence find the value of $q$\\
(d) Find (i) $\mathrm { P } \left( ( C \cup S ) \cap G ^ { \prime } \right)$\\
(ii) $\mathrm { P } ( C \mid ( S \cap G ) )$

A youth club consists of a large number of teenagers.\\
In this youth club 76 teenagers play Chess and Go.\\
(e) Use the information in the Venn diagram to estimate how many of the teenagers in the youth club do not play Scrabble.

\hfill \mbox{\textit{Edexcel S1 2024 Q6 [13]}}