A marketing researcher investigated whether the genre of background music played in a supermarket influences the country of origin of the wine purchased by customers. Over a three-week period, the researcher rotated the background music daily and recorded the number of bottles of wine sold from different regions.
The frequency of purchases under each music condition is shown in the table below:
| Background Music | French Wine | Italian Wine | Spanish Wine | German Wine |
|---|---|---|---|---|
| Classical | 42 | 21 | 11 | 14 |
| Pop | 18 | 35 | 22 | 15 |
| No Music | 15 | 18 | 25 | 30 |
Calculate the degrees of freedom for a Chi-square 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.