A marine biologist wants to investigate whether the concentration of microplastic particles in the digestive tracts of bivalves is affected by their habitat depth.
The researcher needs a stratified sample of 50 bivalves from a coastal reef. The reef contains a population of 300 mussels (which inhabit the shallower intertidal zone) and 200 oysters (which inhabit the deeper subtidal zone).
The biologist plans to extract and count the number of synthetic microfibres found in each bivalve's digestive tract.
Explain one advantage of using a stratified sample of bivalves in this study.
Practise AQA A Level Psychology Scientific processes with exam-style questions for A Level Psychology. 689 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.
