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Averages are fundamental to data analysis. Students must calculate mean, median, mode and range from raw data, frequency tables and grouped data, and understand which average is most appropriate in different contexts.
Students make these errors again and again. Knowing them in advance gives you a head start.
Forgetting to order the data before finding the median
Dividing by the number of groups instead of the total frequency when finding the mean from a table
Using the class boundaries instead of midpoints for grouped frequency means
Insights pulled from Cambridge IGCSE (0580) examiner reports — the exact mistakes candidates make every year.
In probability without replacement, the denominator DECREASES by 1 for each subsequent pick (13 → 12 → 11...). Getting 104/169 instead of the correct answer usually means you forgot this.
Source: CIE 0580 · Feb/March 2024 · Paper 2 · Q25
For 'exactly one green button' out of two picks, there are TWO orderings: green-then-not OR not-then-green. Calculate one product and DOUBLE it (or add both products).
Source: CIE 0580 · May/June 2023 · Paper 4 · Q15
In a histogram, bar HEIGHT = frequency density (frequency ÷ class width). Find the scale using a bar whose frequency AND width you know, then apply it to the others.
Source: CIE 0580 · Feb/March 2022 · Paper 4 · Q5b
Based on 3of 500+ insights extracted from CIE 0580 examiner reports (2018–2024).
This topic appears in the Cambridge IGCSE past papers. Our AI tutor can help with it on any question.
Useful for this topic:
Frequency tables organise raw data into categories or class intervals for analysis. Students must construct tables, calculate totals, and use them to find averages and draw statistical diagrams.
Cumulative frequency diagrams show running totals and are used to estimate the median, quartiles and interquartile range. Students draw the characteristic S-shaped curve and read off values at key percentile positions.
Box plots (box-and-whisker diagrams) display the five-number summary of a dataset and are ideal for comparing distributions. Students draw, interpret and compare box plots, calculating the interquartile range and identifying skewness.
Take our free diagnostic quiz to find out exactly where you stand, then practise statistics with our AI tutor.
Worked examples and data interpretation guides