Worked example · PSE / Well-being · Year 9
DCF: Citizenship → Health and well-being
A secure Year 9 response, annotated so you can see which success criterion each part meets. It is also your answer key. School-night averages: 7.1 hours (Week 1) and 8.1 hours (Week 2); minutes to fall asleep 84 and 24; times woken by phone 6 and 0; energy 2.0 and 3.6. Step 5 is private, so no example is given for it.
| Night | Asleep → woke | Hours asleep | Lights out → asleep (minutes) | Woken by phone | Energy next day |
|---|---|---|---|---|---|
| Sunday | 00:00 → 07:00 | 7 h = 7 | 22:30 → 00:00 = 90 | 1 | 2 |
| Monday | 23:45 → 07:00 | 7 h 15 min = 7.25 | 22:30 → 23:45 = 75 | 1 | 2 |
| Tuesday | 23:30 → 07:00 | 7 h 30 min = 7.5 | 22:30 → 23:30 = 60 | 0 | 3 |
| Wednesday | 00:30 → 07:00 | 6 h 30 min = 6.5 | 22:30 → 00:30 = 120 | 2 | 1 |
| Thursday | 23:45 → 07:00 | 7 h 15 min = 7.25 | 22:30 → 23:45 = 75 | 1 | 2 |
| Friday | 01:15 → 09:45 | 8 h 30 min = 8.5 | 23:00 → 01:15 = 135 | 1 | 3 |
| Saturday | 01:00 → 10:30 | 9 h 30 min = 9.5 | 23:00 → 01:00 = 120 | 0 | 4 |
| Night | Asleep → woke | Hours asleep | Lights out → asleep (minutes) | Woken by phone | Energy next day |
|---|---|---|---|---|---|
| Sunday | 22:45 → 07:00 | 8 h 15 min = 8.25 | 22:30 → 22:45 = 15 | 0 | 4 |
| Monday | 22:45 → 07:00 | 8 h 15 min = 8.25 | 22:30 → 22:45 = 15 | 0 | 4 |
| Tuesday | 23:00 → 07:00 | 8 h = 8 | 22:30 → 23:00 = 30 | 0 | 3 |
| Wednesday | 22:45 → 07:00 | 8 h 15 min = 8.25 | 22:30 → 22:45 = 15 | 0 | 4 |
| Thursday | 23:15 → 07:00 | 7 h 45 min = 7.75 | 22:30 → 23:15 = 45 | 0 | 3 |
| Friday | 23:30 → 08:30 | 9 h = 9 | 23:00 → 23:30 = 30 | 0 | 4 |
| Saturday | 23:15 → 08:45 | 9 h 30 min = 9.5 | 23:00 → 23:15 = 15 | 0 | 4 |
Every night that crosses midnight is handled correctly (00:00 to 07:00 is 7 hours; 22:30 to 00:30 is 120 minutes), and each time is also written as a decimal ready for averaging. Evidences criterion 1.
| Measure | Week 1 | Week 2 | Difference |
|---|---|---|---|
| Average hours asleep, school nights | 35.5 ÷ 5 = 7.1 | 40.5 ÷ 5 = 8.1 | +1.0 hour a night |
| Average hours asleep, Friday and Saturday | 18 ÷ 2 = 9.0 | 18.5 ÷ 2 = 9.25 | +0.25 hours |
| Average minutes to fall asleep, school nights | 420 ÷ 5 = 84 | 120 ÷ 5 = 24 | 60 minutes quicker |
| Total times woken by phone | 6 | 0 | 6 fewer |
| Average energy after school nights | 10 ÷ 5 = 2.0 | 18 ÷ 5 = 3.6 | +1.6 points |
Compares school nights with school nights and weekends with weekends, so Friday's and Saturday's lie-ins do not hide the difference, and shows the totals so the averages can be checked. Evidences criterion 1.
Bars start at zero so the differences are not exaggerated, the two weeks can be told apart in black and white, and the 7-hour line makes Wednesday of Week 1 stand out at once. Evidences criterion 2.
(a) The biggest change is how long she took to fall asleep on school nights: an average of 84 minutes in Week 1 and 24 minutes in Week 2, an hour quicker. In Week 2 she was inside the “about 30 minutes” the experts say is normal.
(b) Her Week 1 school-night average of 7.1 hours is only just above the 7-hour warning level, and well short of the 9 to 9.5 hours most teenagers need. On Wednesday of Week 1 she slept only 6.5 hours, and the note says a group chat went on late: she last looked at her phone at 00:15. In Week 2 her average was 8.1 hours and no night went below 7.75 hours. That is still under 9, so the change helped but did not solve everything.
(c) In Week 1 she woke at 09:45 and 10:30, which is 2 hours 45 minutes and 3 hours 30 minutes later than a school day. In Week 2 it was 08:30 and 08:45, only 1 hour 30 minutes and 1 hour 45 minutes later. A long lie-in means she has been awake for fewer hours by bedtime, and it moves her body clock later, like jet lag, so the next night she is not sleepy at 22:30.
(d) First, it is one person for two weeks, and seven nights of each is not enough to rule out chance. Second, other things changed as well as the phone: Week 1 had a group chat that went on late and a film in bed, while in Week 2 she was worried about a test on Thursday and still slept worst that night, so her sleep depends on more than her phone. Third, the times are her own estimates and the energy scores are her own opinion, and because she knew what she was testing, she may have expected Week 2 to feel better. Even the Chief Medical Officers say the research shows a link between screens and problems, not proof of cause, and this diary is the same: it fits the advice, but it does not prove it.
Figures are quoted with units and compared with the expert advice, the outlier is explained from the notes, and (d) gives three different kinds of reason — sample size, other changes, and how the data was collected — rather than three versions of one. Evidences criteria 3 and 4.
Private, so there is no example. A secure plan changes one thing (for example “no screens after 21:30 on school nights”), records the same things every night (the time you fall asleep, the time you wake, how you feel), keeps everything else as normal as possible, and decides before starting what result would count as it working. Evidences criterion 5.