| Exam Board | Edexcel |
|---|---|
| Module | AS Paper 2 (AS Paper 2) |
| Year | 2021 |
| Session | November |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Data representation |
| Type | Describe or suggest sampling method |
| Difficulty | Easy -1.8 This is a straightforward recall question about sampling methods and the large data set, requiring students to identify systematic sampling and recall specific variables (likely weather type/cloud cover). Part (c) requires basic interpretation but no calculation or complex reasoning. Well below average difficulty for A-level. |
| Spec | 2.01c Sampling techniques: simple random, opportunity, etc |
| Outcome | \(A\) | \(B\) | \(C\) |
| Frequency | 16 | 2 | 1 |
| Outcome | \(A\) | \(B\) | \(C\) |
| Frequency | 16 | 1 | 1 |
| Outcome | \(A\) | \(B\) | \(C\) |
| Frequency | 155 | 26 | 3 |
| Answer | Marks | Guidance |
|---|---|---|
| Systematic (sampling) | B1 | Allow slight misspelling e.g. "sysmatic", "sytmatic". Do NOT allow "systemic" |
| Answer | Marks | Guidance |
|---|---|---|
| [Daily Mean] Wind Speed | B1 {LDS mark} | Allow "Wind speed" or "Wind strength" but NOT just "wind" or "wind direction" |
| Answer | Marks | Guidance |
|---|---|---|
| Light | B1 {LDS mark} | Allow just "light" or "most light". These two B marks are independent so can score B0B1 e.g. "rainfall" and "light" |
| Answer | Marks | Guidance |
|---|---|---|
| Variable \(A\) occurs most (around 80~90%) of the time | B1 | For inferring that frequency of \(A\) can be estimated fairly reliably: {underestimates \(B\) and over estimates \(C\)}. e.g. "\(A\) is the most frequent" [can then ignore comments about \(B\) and \(C\)] |
# Question 3:
## Part (a)
Systematic (sampling) | B1 | Allow slight misspelling e.g. "sysmatic", "sytmatic". Do NOT allow "systemic"
## Part (b)(i)
[Daily Mean] Wind Speed | B1 {LDS mark} | Allow "Wind speed" or "Wind strength" but NOT just "wind" or "wind direction"
## Part (b)(ii)
Light | B1 {LDS mark} | Allow just "light" or "most light". These two B marks are independent so can score B0B1 e.g. "rainfall" and "light"
## Part (c)
Variable $A$ occurs most (around 80~90%) of the time | B1 | For inferring that frequency of $A$ can be estimated fairly reliably: {underestimates $B$ and over estimates $C$}. e.g. "$A$ is the most frequent" [can then ignore comments about $B$ and $C$]
---\begin{enumerate}
\item Helen is studying one of the qualitative variables from the large data set for Heathrow from 2015.
\end{enumerate}
She started with the data from 3rd May and then took every 10th reading.\\
There were only 3 different outcomes with the following frequencies
\begin{center}
\begin{tabular}{ | l | c | c | c | }
\hline
Outcome & $A$ & $B$ & $C$ \\
\hline
Frequency & 16 & 2 & 1 \\
\hline
\end{tabular}
\end{center}
(a) State the sampling technique Helen used.\\
(b) From your knowledge of the large data set\\
(i) suggest which variable was being studied,\\
(ii) state the name of outcome $A$.
George is also studying the same variable from the large data set for Heathrow from 2015. He started with the data from 5th May and then took every 10th reading and obtained the following
\begin{center}
\begin{tabular}{ | l | c | c | c | }
\hline
Outcome & $A$ & $B$ & $C$ \\
\hline
Frequency & 16 & 1 & 1 \\
\hline
\end{tabular}
\end{center}
Helen and George decided they should examine all of the data for this variable for Heathrow from 2015 and obtained the following
\begin{center}
\begin{tabular}{ | l | c | c | c | }
\hline
Outcome & $A$ & $B$ & $C$ \\
\hline
Frequency & 155 & 26 & 3 \\
\hline
\end{tabular}
\end{center}
(c) State what inference Helen and George could reliably make from their original samples about the outcomes of this variable at Heathrow, for the period covered by the large data set in 2015.
\hfill \mbox{\textit{Edexcel AS Paper 2 2021 Q3 [4]}}