Marcus investigated the effectiveness of a new aggression replacement training (ART) programme for adult offenders on probation. He allocated the first 12 offenders who arrived at the probation office on Monday morning to the treatment group, and the first 12 offenders who arrived on Friday afternoon to the control group.
Explain one weakness of Marcus's investigation into the new aggression replacement training programme.
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.
