Worked example · IT · Year 7
LNF: Numeracy → Learning that statistics represent data and that probability models chance helps us make informed inferences and decisions → Collecting data
A secure Year 7 response, annotated so you can see which success criterion each part meets. It is also the answer key. Key figures: 7 backup answers fit two draft boxes and 1 fits none; fixed frequencies 4, 7, 4, 3, 2 (total 20); the most common group is 30 to 59 minutes; the app used most is the school learning platform (8 of 20). Step 5 answers will differ from group to group.
How long do Year 7 pupils spend on homework apps each evening, and which app do they use most?
| Q | What is wrong? | Why will it give bad data? |
|---|---|---|
| 1 | Not needed for the question; private information | Names and addresses do not help answer the question. People may refuse to take part, or not be honest, if they have to give their address. |
| 2 | Leading | “Don’t you agree” pushes people to say yes, so the answers show what the Digital Leaders think, not what pupils think. |
| 3 | Overlapping boxes; missing boxes | 30, 60 and 90 are in two boxes each, so people could tick either one. There is no box for more than 120 minutes. |
| 4 | Vague | “A lot” means different things to different people, and yes or no does not tell us how long. |
| 5 | Two questions in one | Someone might use 3 apps and like only 1. One answer cannot show both things, and open answers are hard to count. |
| 6 | Missing boxes | Pupils who use a different app, or no app, cannot answer, so they will tick a wrong box or leave it blank. |
Each problem is named and linked to the effect it has on the data. Evidences criteria 1 and 2.
(a) On a normal school evening, how many minutes do you spend on homework apps? Tick one box.
☐ 0 to 29 minutes ☐ 30 to 59 minutes ☐ 60 to 89 minutes ☐ 90 to 119 minutes ☐ 120 minutes or more
(b) Which app do you use most for homework? Tick one box.
☐ School learning platform ☐ Maths practice app ☐ Video website ☐ Online dictionary ☐ Other (write it here: ________) ☐ I do not use apps for homework
Every whole number of minutes fits exactly one box: 29 and 30 are in different boxes, and “120 minutes or more” catches the long times. “Other” and “I do not use apps” give everyone a box. Evidences criterion 3.
A group of 5 got: 0 to 29 minutes, 1; 30 to 59 minutes, 3; 60 to 89 minutes, 1; the other groups, 0. Total 5, which matches the 5 people asked.
Nobody found it hard to choose a box, but one person said it depends on the night. That tells us the question should say “on a normal school evening”.
The total is checked against the number of people asked. Evidences criterion 4.
(a) 7 answers could go in two draft boxes: 30, 30, 60, 60, 60, 90 and 90. 1 answer, 150, fits no box, because the last box stops at 120.
(b)
| Time spent each evening | Answers | Frequency |
|---|---|---|
| 0 to 29 minutes | 0, 15, 20, 25 | 4 |
| 30 to 59 minutes | 30, 30, 35, 40, 45, 45, 50 | 7 |
| 60 to 89 minutes | 60, 60, 60, 75 | 4 |
| 90 to 119 minutes | 90, 90, 100 | 3 |
| 120 minutes or more | 120, 150 | 2 |
| Total | 20 |
With the draft boxes, 8 of the 20 answers could be counted wrongly. With the fixed boxes every answer lands in exactly one place, and the total is 20. Evidences criteria 3 and 4.
The most common time is 30 to 59 minutes, which 7 of the 20 pupils chose. The app used most is the school learning platform, used most by 8 of the 20 pupils. The data would be more trustworthy if the Digital Leaders asked the whole of Year 7, not just 20 pupils from one class, because one class might not be typical.
Each sentence is backed by a number from the data, and the last one suggests a better sample. Evidences criterion 5.
Liking question: How much do you like the app you use most? ☐ Very much ☐ Quite a lot ☐ It is OK ☐ Not much ☐ Not at all
Mean: total 1,140 minutes, and 1,140 ÷ 20 = 57 minutes, which is just under 1 hour.
Bar chart: 5 bars with heights 4, 7, 4, 3 and 2, labelled with the time groups, a vertical axis “Number of pupils” from 0 to 8 and a title such as “Time on homework apps each evening, 20 Year 7 pupils”.