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Inferential testing (A-level only)

Inferential testing (A-level only)

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Question 3

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.

Table 1: Observed counts of starfish by species and substrate type

Sandy SeabedRocky ReefMuddy SedimentSeagrass Meadow
Species X (Luidia ciliaris)54123321
Species Y (Astropecten irregularis)7881539

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.

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Markscheme

Inferential testing (A-level only) Questions

  1. A Level
  2. /Psychology
  3. /Inferential testing (A-level only)

121 exam-style questions on AQA A Level Psychology Inferential testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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