A marine biology team collected data from various coastal reefs and found a strong positive correlation between the population density of cleaner wrasse (Labroides dimidiatus, a small fish that feeds on ectoparasites) and the overall biodiversity index of the reef.
Explain why it would not be appropriate to conclude that increasing the population of cleaner wrasse directly causes an increase in reef biodiversity.
19 exam-style questions on AQA A Level Psychology Correlations. Each one has a worked solution and a mark scheme showing where the marks go.