| Exam Board | WJEC |
| Module | Further Unit 5 (Further Unit 5) |
| Year | 2022 |
| Session | June |
| Topic | Wilcoxon tests |
6. A zoologist knows that the median body length of adults in a species of fire-bellied toads is 4.2 cm . The zoologist thinks he has discovered a new subspecies of fire-bellied toads. If there is sufficient evidence to suggest the median body length differs from 4.2 cm , he will continue his studies to confirm whether he has discovered a new subspecies. Otherwise, he will abandon his studies on fire-bellied toads.
The lengths of 10 randomly selected adult toads from the group being investigated are given below.
$$\begin{array} { l l l l l l l l l l }
5 \cdot 0 & 3 \cdot 2 & 4 \cdot 9 & 4 \cdot 0 & 3 \cdot 3 & 4 \cdot 2 & 6 \cdot 1 & 4 \cdot 3 & 4 \cdot 8 & 5 \cdot 9
\end{array}$$
Carry out a suitable Wilcoxon signed rank test at a significance level as close to \(1 \%\) as possible and give your conclusion in context.