| Exam Board | AQA |
|---|---|
| Module | Paper 3 (Paper 3) |
| Year | 2020 |
| Session | June |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Data representation |
| Type | Compare distributions using stem-and-leaf |
| Difficulty | Easy -1.8 This is a straightforward statistics question requiring only basic interpretation of a box plot (comparing medians and IQRs) and recall of data collection issues from the Large Data Set specification. No calculations, problem-solving, or mathematical reasoning required—purely descriptive comparison and memorized critique points about sampling/data quality. |
| Spec | 2.01d Select/critique sampling: in context2.02f Measures of average and spread |
| Answer | Marks |
|---|---|
| 12(a) | Compares correctly the medians |
| Answer | Marks | Guidance |
|---|---|---|
| used, must be correct | 2.2b | E1 |
| Answer | Marks | Guidance |
|---|---|---|
| must be correct | 2.2b | E1 |
| Answer | Marks | Guidance |
|---|---|---|
| 12(b) | Gives one reason why his | |
| conclusion may be invalid | 2.4 | E1 |
| Answer | Marks | Guidance |
|---|---|---|
| OE | 2.4 | E1 |
| Total | 4 | |
| Q | Marking Instructions | AO |
Question 12:
--- 12(a) ---
12(a) | Compares correctly the medians
and infers that London is greater
Must use median only
References to values (London
142 and North West 129), if
used, must be correct | 2.2b | E1 | Central tendency
Median in London is greater than
the median in the North West
Spread
Range in London is less than the
range in the North West
Compares correctly the ranges
and infers that London is less
or
compares correctly the
IQR/SIQR and infers that
London’s IQR/SIQR is greater
Must use range/IQR/SIQR only
References to values, range
(London 307 and North West
343) /IQR (London 49 and North
West 37) /SIQR (London 143.5
and North West 136.5) if used,
must be correct | 2.2b | E1
--- 12(b) ---
12(b) | Gives one reason why his
conclusion may be invalid | 2.4 | E1 | Not all makes of car are included in
the database
Not all English regions are included
Gives a second reason why his
conclusion may be invalid
Other reasons
Some values for CO or CO are
2
missing in the LDS
LDS has outliers/skewed
LDS uses CO or CO from cars
2
only
LDS on shows data for cars
registered in 2002 and 2016
Values in the LDS were not
exact or have been rounded
Information not representative of
England
OE | 2.4 | E1
Total | 4
Q | Marking Instructions | AO | Marks | Typical SolutionThe box plot below summarises the CO$_2$ emissions, in g/km, for cars in the Large Data Set from the London and North West regions.
\includegraphics{figure_12}
\begin{enumerate}[label=(\alph*)]
\item Using the box plot, give one comparison of central tendency and one comparison of spread for the two regions.
[2 marks]
\item Jaspal, an environmental researcher, used all of the data in the Large Data Set to produce a statistical comparison of the CO$_2$ and CO emissions in regions of England.
Using your knowledge of the Large Data Set, give two reasons why his conclusions may be invalid.
[2 marks]
\end{enumerate}
\hfill \mbox{\textit{AQA Paper 3 2020 Q12 [4]}}