A researcher investigated whether there is an association between age group (Under 25s vs 25s and over) and preferred method of screen-time reduction (such as limit apps, grayscale screen, or locking the phone away).
Table 1: Number of participants choosing each screen-time reduction method
| Age Group | Limit Apps | Grayscale Screen | Locking Phone Away |
|---|---|---|---|
| Under 25s | 45 | 15 | 20 |
| 25s and over | 30 | 25 | 35 |
Table 2: Extract of the table of critical values for the Chi-Square (χ2\chi^2χ2) test
| Degrees of freedom (df) | 0.10 | 0.05 | 0.01 |
|---|---|---|---|
| 1 | 2.706 | 3.841 | 6.635 |
| 2 | 4.605 | 5.991 | 9.210 |
| 3 | 6.251 | 7.815 | 11.345 |
| 4 | 7.779 | 9.488 | 13.277 |
Using the tables above, what is the critical value at the 5% significance level (p=0.05p = 0.05p=0.05) for the chi-square test calculated on this data?
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.