An occupational psychologist, Dr. Mercer, wants to investigate whether inhaling peppermint essential oil can enhance reaction times among assembly line operators during afternoon shifts. She plans to diffuse the oil throughout the assembly area.
Explain two ways that Dr. Mercer could make sure her investigation is scientific.
638 exam-style questions on Edexcel A Level Psychology Methods. Each one has a worked solution and a mark scheme showing where the marks go.