Researchers conducted a study on the effects of a 4-week sleep hygiene intervention on working adults. Fifty participants were randomly allocated to either the active sleep-hygiene group or to a control group which received no intervention. A standardized sleep questionnaire was used to measure each participant's sleep quality index before the start and at the end of the 4-week period. The change in sleep quality score was calculated. Results showed that individuals in the sleep-hygiene group displayed a significantly higher improvement in sleep quality compared with those in the control group.
Explain why a control group of participants was necessary for 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.
