| Exam Board | OCR |
|---|---|
| Module | PURE |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Topic | Bivariate data |
| Type | Interpret census or real-world data |
| Difficulty | Moderate -0.5 This question tests interpretation of scatter diagrams with real-world census data, requiring conceptual understanding rather than calculation. While it involves multiple parts and requires careful reasoning about causation vs correlation and identifying patterns, the individual components are straightforward: explaining why age groups are compared (they're the same cohort 10 years later), interpreting y=x (population stability), understanding that these ARE causally linked (same people aged), and identifying outliers (universities attract 18-19 year olds). This is easier than average A-level as it requires no mathematical computation, only data interpretation skills. |
| Spec | 2.02c Scatter diagrams and regression lines2.02e Correlation does not imply causation |
| Answer | Marks | Guidance |
|---|---|---|
| Those in age group 8 to 9 in 2001 will be in age group 18 to 19 in 2011 | B1, [1] | or e.g. "Same people". May be implied |
| Answer | Marks | Guidance |
|---|---|---|
| Few people joined (or left) this group, or "Not much change in this group" or "Most have lived there since 2001" | B1, [1] | LAs with a high number of 8-9s in 2001 have a high number of 18-19s in 2011. Most have stayed in the same area since childhood. |
| Answer | Marks | Guidance |
|---|---|---|
| (No) The nos of 18-19s in 2011 is (largely) caused by the nos of 8-9s in 2001, (but this cannot be inferred from the correlation). | B1, [1] | (No) There is a link. They are the same people. Must state or imply that there is a link between \(x\) and \(y\) in this context. |
| Answer | Marks | Guidance |
|---|---|---|
| 3 (or 4 or 5) of the highest five \(y\)-values | B1, [1] | Must not include right-most point |
| Answer | Marks | Guidance |
|---|---|---|
| In these LAs, the no. of 18-19s in 2011 is more than the no. of 8-9s in 2001. In these LAs there are large numbers of 18+ | B1, [1] | e.g. the no. of people in this group in 2011 is more than it was in 2001. Students are aged 18+ so they cause an increase in this age group. Allow numerical example. May be implied. Not just "These are outliers" oe |
| Answer | Marks |
|---|---|
| Right most point indicated | B1, [1] |
# Question 11:
## Part (a):
Those in age group 8 to 9 in 2001 will be in age group 18 to 19 in 2011 | B1, [1] | or e.g. "Same people". May be implied
## Part (b)(i):
Few people joined (or left) this group, or "Not much change in this group" or "Most have lived there since 2001" | B1, [1] | LAs with a high number of 8-9s in 2001 have a high number of 18-19s in 2011. Most have stayed in the same area since childhood.
## Part (b)(ii):
(No) The nos of 18-19s in 2011 is (largely) caused by the nos of 8-9s in 2001, (but this cannot be inferred from the correlation). | B1, [1] | (No) There is a link. They are the same people. Must state or imply that there is a link between $x$ and $y$ in this context.
## Part (c)(i):
3 (or 4 or 5) of the highest five $y$-values | B1, [1] | Must not include right-most point
## Part (c)(ii):
In these LAs, the no. of 18-19s in 2011 is more than the no. of 8-9s in 2001. In these LAs there are large numbers of 18+ | B1, [1] | e.g. the no. of people in this group in 2011 is more than it was in 2001. Students are aged 18+ so they cause an increase in this age group. Allow numerical example. May be implied. Not just "These are outliers" oe
## Part (d):
Right most point indicated | B1, [1] |
---11 A student is investigating changes in the number of residents in Local Authorities in the SouthEast Region between 2001 and 2011. The scatter diagram shows the number $x$ of residents in these Local Authorities in the age group 8 to 9 in 2001 and the number $y$ of residents in the same Local Authorities in the age group 18 to 19 in 2011.\\
\begin{tikzpicture}[
x=0.0012cm,
y=0.0010cm,
font=\rmfamily
]
% 1. Background Grid Lines
\foreach \x in {2000, 4000, 6000, 8000} {
\draw[thin, black] (\x, 0) -- (\x, 12000);
}
\foreach \y in {2000, 4000, 6000, 8000, 10000, 12000} {
\draw[thin, black] (0, \y) -- (8000, \y);
}
% 2. Axes Lines
\draw[-latex, thin] (0, 0) -- (8800, 0);
\draw[-latex, thin] (0, 0) -- (0, 12800);
% 3. Tick Marks and Values
\foreach \x in {0, 2000, 4000, 6000, 8000} {
\draw (\x, 0) -- ++(0, -150) node[below] {\x};
}
\foreach \y in {2000, 4000, 6000, 8000, 10000, 12000} {
\draw (0, \y) -- ++(-150, 0) node[left] {\y};
}
% 4. Axis Labels
\node[anchor=north] at (4000, -1200) {Number of residents in age group 8 to 9 in 2001};
\node[anchor=east, align=left] at (-1800, 6000) {Number of \\ residents in \\ age group \\ 18 to 19 \\ in 2011};
% 5. Data Points
\foreach \Point in {
(1450,1200), (1650,1300), (1600,1700), (1900,1650), (1950,1800),
(2000,1750), (2000,1950), (2200,1700), (2400,1750), (2400,1900),
(2100,2600), (2200,2100), (2300,2300), (2400,2100), (2400,2200),
(2500,2250), (2550,2450), (2550,2850), (2600,2100), (2600,3400),
(2700,2150), (2700,2300), (2750,2500), (2750,2700), (2800,2450),
(2850,2300), (2850,2650), (2900,2600), (2900,2850), (3000,2200),
(3000,2500), (3100,2600), (3100,2900), (3150,2550), (3150,2700),
(3200,2400), (3200,2700), (3200,3150), (3300,2300), (3300,2650),
(3350,2700), (3400,2700), (3400,3100), (3450,3350), (3500,3100),
(3550,3200), (3550,3350), (3600,3100), (3600,3300), (3950,3200),
(4100,3500), (4150,3300), (4400,4100), (4500,3700),
(1800,2900), (3050,4450), (3400,4850), (6250,5150),
(2800,8300), (3200,7900), (4600,9000), (5100,9800), (5400,10600),
(7400,8100)
} {
\fill \Point circle (2.0pt);
}
\end{tikzpicture}
\begin{enumerate}[label=(\alph*)]
\item Suggest a reason why the student is comparing these two age groups in 2001 and 2011.
The student notices that most of the data points are close to the line $y = x$.
\item \begin{enumerate}[label=(\roman*)]
\item Explain what this suggests about the residents in these Local Authorities.
\item The student says that correlation does not imply causation, so there is no causal link between the values of $x$ and the values of $y$.
Explain whether or not they are correct.
\end{enumerate}\item Some of these Local Authorities contain universities.
\begin{enumerate}[label=(\roman*)]
\item On the diagram in the Printed Answer Booklet, circle three points that are likely to represent Local Authorities containing universities.
\item Give a reason for your choice of points in part (c)(i).
Assume that the proportion of residents in age group 8 to 9 in 2001 was roughly the same in each Local Authority in the South-East. The Local Authority in this region with the largest population is Medway.
\end{enumerate}\item On the diagram in the Printed Answer Booklet, label clearly with the letter $M$ the point that corresponds to Medway.
\end{enumerate}
\hfill \mbox{\textit{OCR PURE Q11 [6]}}