| Exam Board | AQA |
|---|---|
| Module | Further AS Paper 2 Statistics (Further AS Paper 2 Statistics) |
| Year | 2024 |
| Session | June |
| Marks | 1 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Chi-squared test of independence |
| Type | Cell combining required |
| Difficulty | Easy -1.2 This is a straightforward recall question testing knowledge of the chi-squared test validity condition (expected frequencies ≥ 5). Students simply need to identify that Expected B-Y = 3 violates this rule, requiring no calculation or problem-solving beyond recognizing a standard criterion. |
| Spec | 5.06a Chi-squared: contingency tables |
| Observed | X | Y | Z |
| A | 28 | 6 | 66 |
| B | 8 | 8 | 4 |
| C | 54 | 16 | 10 |
| Expected | \(\mathbf { X }\) | \(\mathbf { Y }\) | \(\mathbf { Z }\) |
| \(\mathbf { A }\) | 45 | 15 | 40 |
| \(\mathbf { B }\) | 9 | 3 | 8 |
| \(\mathbf { C }\) | 36 | 12 | 32 |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Marks | Guidance |
| Circles the \(4^{th}\) answer: Expected B-Y | B1 | AO 1.1b |
## Question 2:
| Answer | Marks | Guidance |
|--------|-------|----------|
| Circles the $4^{th}$ answer: Expected B-Y | B1 | AO 1.1b |
**Question total: 1 mark**
---2 A test for association is to be carried out.
The tables below show the observed frequencies and the expected frequencies that are to be used for the test.
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Observed & X & Y & Z \\
\hline
A & 28 & 6 & 66 \\
\hline
B & 8 & 8 & 4 \\
\hline
C & 54 & 16 & 10 \\
\hline
\end{tabular}
\end{center}
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Expected & $\mathbf { X }$ & $\mathbf { Y }$ & $\mathbf { Z }$ \\
\hline
$\mathbf { A }$ & 45 & 15 & 40 \\
\hline
$\mathbf { B }$ & 9 & 3 & 8 \\
\hline
$\mathbf { C }$ & 36 & 12 & 32 \\
\hline
\end{tabular}
\end{center}
It is necessary to merge some rows or columns before the test can be carried out.\\
Find the entry in the tables that provides evidence for this.\\
Circle your answer.\\[0pt]
[1 mark]\\
Observed A-Z\\
Observed B-Z\\
Expected A-X\\
Expected B-Y
\hfill \mbox{\textit{AQA Further AS Paper 2 Statistics 2024 Q2 [1]}}