OCR MEI Further Statistics Minor Specimen — Question 1 4 marks

Exam BoardOCR MEI
ModuleFurther Statistics Minor (Further Statistics Minor)
SessionSpecimen
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicGeometric Distribution
TypeGeometric with multiple success milestones
DifficultyModerate -0.8 This is a straightforward application of the geometric distribution with standard formulas. Part (i) requires P(X=10) = (0.95)^9 × 0.05, part (ii) is simply (0.95)^10, and part (iii) is recall of E(X) = 1/p = 20. All three parts are direct formula application with no problem-solving or conceptual challenge, making this easier than average even for Further Maths.
Spec5.02f Geometric distribution: conditions5.02g Geometric probabilities: P(X=r) = p(1-p)^(r-1)

A darts player is trying to hit the bullseye on a dart board. On each throw the probability that she hits it is \(0.05\), independently of any other throw.
  1. Find the probability that she hits the bullseye for the first time on her \(10\)th throw. [2]
  2. Find the probability that she does not hit the bullseye in her first \(10\) throws. [1]
  3. Write down the expected number of throws which it takes her to hit the bullseye for the first time. [1]

Question 1:
AnswerMarks Guidance
1(i) 0.959 × 0.05
= 0.0315M1
A1
AnswerMarks
[2]3.3
1.1
AnswerMarks Guidance
1(ii) 0.9510 = 0.599
[1]1.1
1(iii) 1
(cid:32) 20
AnswerMarks Guidance
0.05B1
[1]1.1 N
Question 1:
1 | (i) | 0.959 × 0.05
= 0.0315 | M1
A1
[2] | 3.3
1.1
1 | (ii) | 0.9510 = 0.599 | B1
[1] | 1.1
1 | (iii) | 1
(cid:32) 20
0.05 | B1
[1] | 1.1 | N
A darts player is trying to hit the bullseye on a dart board. On each throw the probability that she hits it is $0.05$, independently of any other throw.

\begin{enumerate}[label=(\roman*)]
\item Find the probability that she hits the bullseye for the first time on her $10$th throw. [2]

\item Find the probability that she does not hit the bullseye in her first $10$ throws. [1]

\item Write down the expected number of throws which it takes her to hit the bullseye for the first time. [1]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI Further Statistics Minor  Q1 [4]}}