Dr. Vance conducted an investigation to determine whether inhaling rosemary essential oil improves cognitive alertness compared to a control condition with no scent. She matched participants on their initial cognitive processing speed to form pairs; one member of each pair completed an alertness task in a room scented with rosemary, while the other completed it in an unscented room. The level of alertness was measured using a 10-point subjective rating scale, yielding ordinal data.
Identify three reasons why Dr. Vance should use the Wilcoxon signed-ranks test to analyse her data.
Practise Edexcel A Level Psychology Methods with exam-style questions for A Level Psychology. 638 questions, 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.