Marcus conducted an investigation into the effectiveness of a new aggression-reduction programme for violent offenders. As part of his research, he compared the self-reported impulsivity scores of the participants before they started the cognitive-behavioural programme with their scores after they completed the final session.
Identify the experimental design Marcus used in this experiment.
51 exam-style questions on Edexcel A Level Psychology Research methods and skills, covering Research methods and skills. Each one has a worked solution and a mark scheme showing where the marks go.