Statistics · Cumulative frequency & box plots
Chapter 1 · 3
The idea
Box plots
What each of the five marks on a box plot means, why the box holds the middle 50% of the data, and why a longer section means the data there is more spread out — never that there is more of it.
A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.
In this lesson — start anywhere
Statistics · Cumulative frequency & box plots
Box plots
What each of the five marks on a box plot means, why the box holds the middle 50% of the data, and why a longer section means the data there is more spread out — never that there is more of it.
Why it works
Not a picture of how many
A box plot is not a picture of how many. It is a picture of *where the values sit*. Almost every mark lost on box plots comes from forgetting that one sentence, so it is worth seeing exactly where the five marks on the plot come from.Start with data, in order. Here are the marks of students in a test out of , with a bar dropped after every fifth value:
Keep reading — free
The rest of the explanation, plus 3 worked examples you step through move by move.
Start freeTakes a minute — no card.