Marcus conducted a study to investigate whether shoppers are more likely to comply with a request to sign a petition depending on what the person asking is wearing. He used two conditions: a researcher dressed in high-vis workwear, and the same researcher dressed in casual clothing (jeans and a t-shirt).
He recorded the number of shoppers who agreed to sign the petition and those who refused in each condition. The results are shown in Table 1.
| Person in high-vis workwear | Person in casual clothes | |
|---|---|---|
| Approved and signed the petition | 18 | 6 |
| Declined to sign the petition | 12 | 24 |
Explain one improvement that could be made to the experimental design used in Marcus's research.
Practise Edexcel A Level Psychology Research methods and skills with exam-style questions for A Level Psychology. 657 questions covering Research methods and skills, matched to the Edexcel A Level Psychology (9PS0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
