Freya conducted a laboratory experiment to investigate the effect of caffeine on memory. She used an independent groups design where 10 participants drank a high-caffeine energy drink and 10 participants drank still water. Each participant was then given exactly 2 minutes to memorise a list of 20 abstract words before being asked to recall as many as possible. Freya used opportunity sampling, selecting the first 20 students she met in the university library during exam week to take part in the study.
Explain one improvement that Freya could make to her investigation.
38 exam-style questions on Edexcel A Level Psychology Synoptic review of studies. Each one has a worked solution and a mark scheme showing where the marks go.