A retail researcher investigated whether there was an association between a shopper's age group (under 30 years old versus 30 years old and over) and their preferred checkout method (self-service checkout versus staffed checkout).
An observational study was conducted during peak weekend hours at a major supermarket, tracking randomly selected shoppers who completed their purchases.
The collected data is presented below:
| Self-service checkout | Staffed checkout | |
|---|---|---|
| Under 30 years old | 84 | 31 |
| 30 years old and over | 45 | 68 |
Explain why the Chi-Square (χ2\chi^2χ2) test is the correct non-parametric statistical test to use to analyse the data in this study.
644 exam-style questions on OCR A Level Psychology Research methods and techniques. Each one has a worked solution and a mark scheme showing where the marks go.