Section A: Data and Representation
- Distinguish qualitative and quantitative data.
- Define population and sample.
- Find a class width from 15≤x<25.
- Find the pie-chart angle for 24 out of 80.
- State one difference between a bar chart and histogram.
Section B: Averages and Spread
- Find mean, median and mode of 4,5,5,6,10.
- Given Q₁=21 and Q₃=39, find IQR and semi-IQR.
- Find midpoint of 40≤x<60.
- Explain why mean may be unsuitable when there is a large outlier.
Section C: Grouped Data and Evaluation
- Find density when frequency=32 and width=8.
- For N=100, state Q₁, median and Q₃ positions.
- Explain why histogram area represents frequency.
- Identify one problem with surveying only volunteers.
- Explain why correlation does not prove causation.
🏁 Final Checkpoint: Instant Marking
✅ Check Your Work
Show answers and working
- Qualitative data are categories/descriptions; quantitative data are numerical.
- Population: entire group; sample: selected subset.
- 25−15=10.
- 24÷80×360=108°.
- Bar-chart bars are separated categories; histogram bars touch for continuous intervals.
- Mean=30÷5=6; median=5; mode=5.
- IQR=39−21=18; semi-IQR=9.
- 50.
- The extreme value pulls the mean away from the typical values.
- 32÷8=4.
- Q₁=25th, median=50th, Q₃=75th.
- For unequal widths, area=density×width=frequency.
- Volunteers may differ systematically from non-volunteers, creating self-selection bias.
- A third factor or coincidence may explain the association; an experiment or stronger evidence is needed for causation.
Celebration
You can now collect, organise, display, analyse and question data—not just calculate with it.
Revision Guidance and Readiness
- Attempt the questions without notes first.
- Use the answers or worked solutions to identify the exact step that needs attention.
- Return to the relevant lesson, then retry missed questions.
- You are ready to move on when you can explain your method and check your result independently.