| Exam Board | WJEC |
|---|---|
| Module | Further Unit 2 (Further Unit 2) |
| Year | 2019 |
| Session | June |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Hypothesis test of Spearman’s rank correlation coefficien |
| Type | Calculate and interpret coefficient |
| Difficulty | Standard +0.3 This is a straightforward application of Spearman's rank correlation coefficient formula with data already ranked. Part (a) requires basic conceptual understanding (any monotonic non-linear relationship), part (b) is routine calculation with n=8, and part (c) is standard interpretation. Slightly easier than average due to small dataset and no hypothesis testing required despite the topic description. |
| Spec | 5.08e Spearman rank correlation5.08f Hypothesis test: Spearman rank |
| Cheese | A | B | C | D | E | F | G | H |
| Judge 1 | 1 | 5 | 8 | 7 | 6 | 4 | 3 | 2 |
| Judge 2 | 1 | 3 | 8 | 5 | 2 | 4 | 6 | 7 |
| Answer | Marks | Guidance |
|---|---|---|
| 1 | Birth Month | Observed |
Question 1:
1 | Birth Month | Observed | Expected\begin{enumerate}
\item (a) Sketch a scatter diagram of a dataset for which Spearman's rank correlation coefficient is + 1 , but the product moment correlation coefficient is less than 1 .
\end{enumerate}
Two judges were judging cheese at the UK Cheese Festival. There were 8 blue cheeses in a particular category. The rankings are shown below.
\begin{center}
\begin{tabular}{|l|l|l|l|l|l|l|l|l|}
\hline
Cheese & A & B & C & D & E & F & G & H \\
\hline
Judge 1 & 1 & 5 & 8 & 7 & 6 & 4 & 3 & 2 \\
\hline
Judge 2 & 1 & 3 & 8 & 5 & 2 & 4 & 6 & 7 \\
\hline
\end{tabular}
\end{center}
(b) Calculate Spearman's rank correlation coefficient for this dataset.\\
(c) By sketching a scatter diagram of the rankings, or otherwise, comment on the extent to which the judges agree.\\
\hfill \mbox{\textit{WJEC Further Unit 2 2019 Q1 [7]}}