A psychologist investigates confidence when giving a short talk. The target population is all 240 adults enrolled at a community learning centre. The psychologist emails all 240 adults with an invitation to take part. The 30 adults who reply each give their confidence a rating from 1 to 10.
| Age group | Number in target population | Number in sample | Mean confidence rating in sample |
|---|---|---|---|
| 18–29 | 80 | 18 | 8.0 |
| 30–49 | 80 | 9 | 6.0 |
| 50 and over | 80 | 3 | 4.0 |
Identify the sampling method used by the psychologist.
Using the data in the table, explain why the findings may not generalise to the target population.
182 exam-style questions on OCR GCSE Psychology 7.1 Planning Research, covering 7.1.1 Hypotheses, 7.1.2 Variables, 7.1.3 Experimental Designs, 7.1.4 Populations and Sampling, 7.1.5 Ethical issues, and 7.1.6 Dealing with ethical issues and BPS Code. Each one has a worked solution and a mark scheme showing where the marks go.