| Exam Board | WJEC |
|---|---|
| Module | Further Unit 5 (Further Unit 5) |
| Year | 2024 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Wilcoxon tests |
| Type | Wilcoxon rank-sum test (Mann-Whitney U test) |
| Difficulty | Standard +0.8 This is a standard Mann-Whitney U test application requiring ranking of combined data, calculation of U statistics, and comparison with critical values. While methodical, it involves multiple computational steps (ranking 21 values, summing ranks, calculating U and U', finding critical value) with opportunity for arithmetic errors. The procedure is well-defined but time-consuming for a 6-mark question, placing it moderately above average difficulty. |
| Spec | 5.07a Non-parametric tests: when to use |
| Group A | 32 | 8 | 24 | 16 | 10 | 20 | 22 | 18 | 23 | 21 | 26 | 14 |
| Group B | 30 | 29 | 11 | 25 | 38 | 36 | 28 | 12 | 17 |
Alana is a PhD student researching language acquisition. She gives one group of randomly selected participants, Group A, 4 minutes to memorise 40 words that are similar in meaning. She gives a different, randomly selected group of participants, Group B, 4 minutes to memorise 40 words that are different in meaning. Alana believes that the students in Group B will do better than the students in Group A. The following results are the number of words recalled on testing the students from the two groups.
\begin{center}
\begin{tabular}{|l|c|c|c|c|c|c|c|c|c|c|c|}
\hline
Group A & 32 & 8 & 24 & 16 & 10 & 20 & 22 & 18 & 23 & 21 & 26 & 14 \\
\hline
Group B & 30 & 29 & 11 & 25 & 38 & 36 & 28 & 12 & 17 & & & \\
\hline
\end{tabular}
\end{center}
Conduct a Mann-Whitney U test at a significance level as close as possible to 5\% to test Alana's belief. [6]
\hfill \mbox{\textit{WJEC Further Unit 5 2024 Q6 [6]}}