A marine biologist is investigating whether there is an association between different species of starfish and their preferred seabed substrate. They conduct a comprehensive survey across a marine conservation zone and record the frequency of each species found on various substrates over a 48-hour period. The observed counts are shown in Table 1 below.
| Sandy Seabed | Rocky Reef | Muddy Sediment | Seagrass Meadow | |
|---|---|---|---|---|
| Species X (Luidia ciliaris) | 54 | 12 | 33 | 21 |
| Species Y (Astropecten irregularis) | 78 | 8 | 15 | 39 |
Upon reviewing the data, the lead scientist remarks, "There appears to be a visible difference in the distribution of the two species across these habitats, but is this association statistically significant at the 0.01 level of significance?"
Explain what the research assistants must do with the data in Table 1 to answer the lead scientist's question. Justify your statistical choices as part of your explanation.
Practise aqa A Level Psychology Inferential testing (A-level only) with exam-style questions for A Level Psychology. 123 questions, matched to the aqa A Level Psychology (7182) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
