Researchers investigated the association between daily screen-time and sleep quality in teenagers. They sampled 60 participants, categorising them as 'High Screen-Time' (3 or more hours per day) or 'Low Screen-Time' (fewer than 3 hours per day) based on device logs, and assessing their sleep quality as 'Good' or 'Poor' using a standardised questionnaire. The raw contingency data is summarised in Table 1.
Table 1: Sleep quality by daily screen-time
| Good Sleep | Poor Sleep | |
|---|---|---|
| High Screen-Time | 8 | 22 |
| Low Screen-Time | 18 | 12 |
Table 2: Critical values of Chi-Square (χ2\chi^2χ2) for df=1df = 1df=1
| Significance Level (ppp) | 0.10 | 0.05 | 0.01 |
|---|---|---|---|
| Critical value (df=1df = 1df=1) | 2.71 | 3.84 | 6.63 |
Using the calculated Chi-square value of χ2=5.12\chi^2 = 5.12χ2=5.12, write a significance statement for the analysis performed 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.