A botanist is investigating the relationship between the moisture content of soil, MMM (measured as a percentage), and the final growth height of a specific seedling species, HHH (measured in cm). The data for 8 test plots are recorded in the table below.
| Plot | A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|---|
| Moisture (MMM %) | 25 | 12 | 38 | 55 | 30 | 42 | 18 | 50 |
| Height (HHH cm) | 18.3 | 10.1 | 25.4 | 32.8 | 15.2 | 28.1 | 14.9 | 20.5 |
Calculate Spearman's rank correlation coefficient for these data.
Stating your hypotheses clearly, test at the 5% level of significance whether there is evidence of a positive correlation between soil moisture content and seedling growth height.
178 exam-style questions on WJEC A Level Maths 4.3.1 Statistical hypothesis testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.