A psychologist compares concentration scores for pupils in single-sex and mixed classes at several schools. Before the study began, the schools had placed pupils in single-sex or mixed classes as part of their normal teaching arrangements. The mean concentration scores are shown below.
| Class setting | Mean concentration score (out of 20) |
|---|---|
| Single-sex | 14.2 |
| Mixed | 12.8 |
Explain why this is a natural experiment and what conclusion can be drawn from the results.
139 exam-style questions on OCR GCSE Psychology 7.2 Doing Research, covering 7.2.1 Experiments, 7.2.2 Interviews, 7.2.3 Questionnaires (Surveys), 7.2.4 Observations, 7.2.5 Case Studies, and 7.2.6 Correlations. Each one has a worked solution and a mark scheme showing where the marks go.