A team of educational psychologists investigated the impact of screen time on the sleep quality of students at a secondary school. They used stratified sampling to select 120 participants, ensuring that different year groups (Year 10, Year 11, and Year 12) were proportionally represented.
Outline one strength of using stratified sampling to obtain the participants for this study.
644 exam-style questions on OCR A Level Psychology Research methods and techniques. Each one has a worked solution and a mark scheme showing where the marks go.