A marine biologist wanted to test if there is a relationship between the dissolved oxygen concentration (measured in mg/L\text{mg/L}mg/L) in a river and the density of mayfly nymphs (measured in count per m2\text{m}^2m2).
They sampled 30 distinct locations along the river, where dissolved oxygen levels varied from 4.5 mg/L to 11.5 mg/L, and recorded the density of mayfly nymphs. The sampling method was standardised at each location using a kick-sampling technique for exactly 3 minutes.
When writing up the investigation, the biologist represented their data on a scattergram.
Briefly explain how the use of inferential statistics would improve this biologist's investigation.
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.