| Exam Board | AQA |
|---|---|
| Module | Paper 3 (Paper 3) |
| Year | 2020 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Matchings and Allocation |
| Type | Bipartite graph definition or properties |
| Difficulty | Easy -1.3 This is a straightforward stratified sampling question requiring basic proportional calculation (4735/13300 × 70 and 8565/13300 × 70) and description of random sampling methodology. Both parts test routine recall of standard sampling procedures with no problem-solving or novel insight required. |
| Spec | 2.01c Sampling techniques: simple random, opportunity, etc |
| Answer | Marks |
|---|---|
| 15(a) | Uses correct proportion to find |
| Answer | Marks | Guidance |
|---|---|---|
| or 46 for 45.1 | 1.1a | M1 |
| Answer | Marks | Guidance |
|---|---|---|
| ISW | 1.1b | A1 |
| Answer | Marks |
|---|---|
| 15(b) | Sets up enumerated population |
| Answer | Marks | Guidance |
|---|---|---|
| range used OE | 2.4 | E1 |
| Answer | Marks | Guidance |
|---|---|---|
| method eg hat or lottery | 2.4 | E1 |
| Answer | Marks | Guidance |
|---|---|---|
| method eg hat or lottery | 2.4 | E1F |
| Total | 5 | |
| Q | Marking Instructions | AO |
Question 15:
--- 15(a) ---
15(a) | Uses correct proportion to find
either category
PI by correct answer
Accept 24 or 25 for 24.9 and 45
or 46 for 45.1 | 1.1a | M1 | × 70 = 24.9
4735
= 25 under 30 years old
13 300
× 70 = 45.1
8565
= 45 above 30 years old
13 300
Obtains the correct number of
under 30 years old and 30 years
old and over
Accept 24 paired with 46
ISW | 1.1b | A1
--- 15(b) ---
15(b) | Sets up enumerated population
using valid numbering stating
range used OE | 2.4 | E1 | Give each member under 30 years
old a number from 1 to 4735
Generate random four-digit
integers using a calculator
Continue until 25 different numbers
have been identified and select the
members given those numbers
Explains how to obtain random
numbers using calculator or
number generator
Must refer to replacement if
using alternative suitable
method eg hat or lottery | 2.4 | E1
Explains how to select their
amount of people under 30
years old ensuring different
numbers chosen OE
Must state ignore repeats if
using alternative suitable
method eg hat or lottery | 2.4 | E1F
Total | 5
Q | Marking Instructions | AO | Marks | Typical SolutionA political party is holding an election to choose a new leader.
A statistician within the party decides to sample 70 party members to find their opinions of the leadership candidates.
There are 4735 members under 30 years old and 8565 members 30 years old and over.
The statistician wants to use a sample of 70 party members in the survey.
He decides to use a random stratified sample.
\begin{enumerate}[label=(\alph*)]
\item Calculate how many of each age group should be included in his sample.
[2 marks]
\item Explain how he could collect the random sample of members under 30 years old.
[3 marks]
\end{enumerate}
\hfill \mbox{\textit{AQA Paper 3 2020 Q15 [5]}}