Dr. Aris conducted a field experiment in a public park to investigate whether people are more likely to obey a directive to pick up a discarded plastic bottle depending on the authority of the person making the request. He used two conditions: in the first, a confederate was dressed in a park ranger's official uniform; in the second, the same confederate was dressed in a plain grey tracksuit.
The confederate approached lone park visitors and said, "Pick up that bottle and throw it in the bin."
Dr. Aris recorded the number of visitors who obeyed the instruction and those who refused in each condition. The results are shown in Table 1.
| Confederate in park ranger uniform | Confederate in plain grey tracksuit | |
|---|---|---|
| Obeyed and disposed of the litter | 22 | 8 |
| Refused to dispose of the litter | 10 | 26 |
Explain one improvement that could be made to the experimental design used in Dr. Aris's research.
88 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.