Cambridge IGCSE·Mathematics 0580·Extended Grouped Data

📋Key knowledge — Statistics

Formulas & equations

Mean = Σfx ÷ Σf (for frequency tables)
Range = maximum − minimum
Interquartile range (IQR) = Q3 − Q1
Median from cumulative frequency: read off at n/2
Q1 at n/4; Q3 at 3n/4
Frequency 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 Extended

4 Cambridge IGCSE 0580 questions on grouped data at the Extended tier — each with its full mark scheme. For the Core 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.