An urban planner investigates whether there is an association between the district of a city a resident lives in and their primary mode of weekend transport. The observed frequencies from a random sample of residents are recorded in the table below:
| District | Private Car | Public Transit | Bicycle | Walking |
|---|---|---|---|---|
| North | 45 | 62 | 18 | 15 |
| South | 30 | 85 | 12 | 23 |
| East | 55 | 40 | 35 | 10 |
| West | 20 | 50 | 45 | 30 |
Calculate the degrees of freedom for use with a Chi-square (χ2\chi^2χ2) test of association for this study. Show your workings.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.