Amara conducted an investigation to evaluate the effectiveness of a new anger management programme for young offenders. She allocated the first 15 offenders who volunteered to the treatment group, and another 15 offenders who were referred later to the control group.
Explain one weakness of Amara's investigation into the new anger management 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.
