Exercise 1 — Cambridge IGCSE 0580 Nov 2024 Paper 31 Q3
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Cambridge IGCSE·Mathematics 0580·Core
Grouped Data
Key knowledge — Statistics
Formulas & equations
Mean = Σfx ÷ Σf (for frequency tables)Range = maximum − minimumInterquartile range (IQR) = Q3 − Q1Median from cumulative frequency: read off at n/2Q1 at n/4; Q3 at 3n/4Frequency density = frequency ÷ class width (for histograms)
Key facts & rules
- Mean uses all values — affected by outliers.
- Median is the middle value when ordered — not affected by outliers.
- Mode is the most frequent value.
- For grouped data: use midpoints to estimate the mean.
- Cumulative frequency graph: S-shaped curve; read median and quartiles from it.
- Box-and-whisker plots: show median, Q1, Q3, min and max.
- Positive correlation: both variables increase together. Negative: one increases as other decreases.
- The line of best fit passes through the mean point (x̄, ȳ).
IGCSE Statistics — Grouped data Practice Core
1 Cambridge IGCSE 0580 questions on grouped data at the Core tier — each with its full mark scheme. For the Extended tier on the same skill, click here.
How to approach grouped data — open the study guide
Grouped data on IGCSE 0580
Estimated mean = Σ(midpoint × frequency) ÷ total frequency. The modal class is the interval with the highest frequency. The median class contains the middle value — use cumulative frequencies to find it.
Practice exercises