Elena conducted a correlational study to investigate whether there was a relationship between daily caffeine intake (measured in milligrams) and the duration of rapid eye movement (REM) sleep (measured in minutes).
Outline one strength and one limitation of using a correlational research design in this investigation.
Practise Edexcel A Level Psychology Research methods and skills with exam-style questions for A Level Psychology. 657 questions covering Research methods and skills, matched to the Edexcel A Level Psychology (9PS0) 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.
