A developmental psychologist wanted to investigate how screen time before bed affects sleep onset latency. Group X (Screen-free) read a paper book for 30 minutes before bed, while Group Y (Screen-use) used a tablet for 30 minutes before bed. Sleep onset latency (the time taken to fall asleep, in minutes) was recorded for each participant. The table below shows the results.
| Group X (Screen-free) | Sleep Latency (mins) | Group Y (Screen-use) | Sleep Latency (mins) |
|---|---|---|---|
| Participant 1 | 18 | Participant 1 | 35 |
| Participant 2 | 24 | Participant 2 | 42 |
| Participant 3 | 15 | Participant 3 | 28 |
| Participant 4 | 21 | Participant 4 | 48 |
| Participant 5 | 30 | Participant 5 | 31 |
| Participant 6 | 17 | Participant 6 | 39 |
| Participant 7 | 25 | Participant 7 | 45 |
| Participant 8 | 26 | Participant 8 | 36 |
Which of these is the mean score of the participants in Group X (Screen-free)?
22.522.522.5
38.038.038.0
22.022.022.0
30.030.030.0
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.