A psychologist investigates whether taking a 10-minute walk improves concentration. Forty adults take part. Twenty adults complete a 10-minute walk and then complete a letter cancellation task. A different 20 adults sit quietly for 10 minutes and then complete the same task.
Before the investigation, all the adults complete a concentration screening test marked out of 30. A higher score indicates better concentration.
| Condition | Mean screening test score out of 30 | Mean number of errors on the letter cancellation task |
|---|---|---|
| 10-minute walk | 24 | 4 |
| Sitting quietly | 18 | 7 |
Using the information and the data, describe the experimental design used and one problem with drawing a conclusion about the effect of the walk.
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.