Dr. Aris conducted a field experiment to investigate the influence of authority clothing on compliance. Two different confederates—one dressed in a formal security guard uniform and another dressed in casual high-street clothes—approached members of the public in a public park and instructed them to pick up a piece of litter. Dr. Aris recorded how many people complied or refused. The findings are summarized in Table 1.
| Security Guard Uniform | Casual Clothes | |
|---|---|---|
| Number of people who complied | 18 | 5 |
| Number of people who refused | 6 | 17 |
Explain one improvement that could be made to the experimental design used in Dr. Aris's research.
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